Ilt-binding agents and methods of use thereof

ABSTRACT

The present disclosure provides binding agents, such as antibodies, that specifically bind ILT2, ILT4, or both ILT2 and ILT4, as well as compositions comprising the binding agents, and methods of their use. The disclosure also provides related polynucleotides and vectors encoding the binding agents and cells comprising the binding agents.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. ProvisionalAppl. No. 63/019,068, filed May 1, 2020; and U.S. Provisional Appl. No.63/122,848, filed Dec. 8, 2020; the contents of both of which areincorporated herein by reference in their entirety.

SEQUENCE LISTING

The present specification is being filed with a computer readable form(CRF) copy of the Sequence Listing. The CRF entitled47702-0094001_SL.txt, which was created on Apr. 26, 2021 and is 178,820bytes in size, is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to agents that bindimmunoglobulin-like transcript (ILT) proteins, particularly antibodiesthat bind to human ILT2, human ILT4, and both human ILT2 and human ILT4,as well as compositions comprising the ILT-binding agents and methods ofusing the binding agents and compositions.

BACKGROUND

The basis for immunotherapy is the manipulation and/or modulation of theimmune system, including both innate immune responses and adaptiveimmune responses. The general aim of immunotherapy is to treat diseasesby controlling the immune response to a “foreign agent”, for example apathogen or a tumor cell. However, in some instances immunotherapy isused to treat autoimmune diseases which may arise from an abnormalimmune response against proteins, molecules, and/or tissues normallypresent in the body. Immunotherapy may include methods to induce orenhance specific immune responses or to inhibit or reduce specificimmune responses.

The immune system is a highly complex system made up of a great numberof cell types, including but not limited to, T-cells, T-cell subsets,B-cells, natural killer cells, antigen-presenting cells, dendriticcells, monocytes, and macrophages. These cells possess complex andsubtle systems for controlling their interactions and responses. Thecells utilize both activating and inhibitory mechanisms and feedbackloops to keep responses in check and not allow negative consequences ofan uncontrolled immune response (e.g., autoimmune diseases or a cytokinestorm).

Some of the inhibitory mechanisms of the immune system use proteins fromthe leukocyte Ig-like receptor (LILR) family. The leukocyte Ig-likereceptor subfamily B (LILRB) is a group of type I transmembraneglycoproteins with extracellular Ig-like domains and cytoplasmicimmunoreceptor tyrosine-based inhibitory motifs (ITIMs). This group ofITIM-containing receptors includes 5 members: LILRB1 (also known asCD85J, LIR1, ILT2), LILRB2 (also known as CD85D, LIR2, ILT4), LILRB3(also known as CD85A, LIR3, ILT5), LILRB4 (also known as CD85K, LIR5,ILT3), and LILRB5 (also known as CD85C, LIR8). The biological functionsand clinical significance of many of these LILRBs (ILTs) are still beinginvestigated. There is also a LILR subfamily A (LILRA) that is a groupof type I transmembrane glycoproteins with extracellular Ig-like domainsand cytoplasmic immunoreceptor tyrosine-based activating motifs (ITAMs).This group of ITAM-containing receptors includes 6 members: LILRA1 (alsoknown as CD85I, LIRE), LILRA2 (also known as CD85H, LIR7, ILT1), LILRA3(also known as CD85E, LIR4, ILT6, monocyte inhibitory receptor HM43/31),LILRA4 (also known as CD85G, ILT7), LILRAS (also known as CD85F, LIR9,ILT11), and LILRA6 (also known as ILT8). The inhibitory and activatingproteins of the LILR family appear to work in concert to modulate immunehomeostasis.

The concept of cancer immunosurveillance is based on the theory that theimmune system can recognize tumor cells, mount an immune response, andsuppress the development and/or growth of a tumor. However, it is clearthat many cancerous/tumor cells have developed mechanisms and/orhijacked normal inhibitory mechanisms to evade the immune system whichcan allow for uninhibited growth of tumor cells. Cancer/tumorimmunotherapy (immuno-oncology) focuses on the development of new andnovel agents that can activate and/or boost the immune system to achievea more effective attack against cancer/tumor cells resulting inincreased killing of cancer/tumor cells and/or inhibition ofcancer/tumor growth.

BRIEF SUMMARY

The present disclosure provides agents that bind immunoglobulin-liketranscript 2 (ILT2) and/or immunoglobulin-like transcript 4 (ILT4).Although the LILRB family members are referred to by many names inpublications, the terms “ILT2” (LILRB1) and “ILT4” (LILRB2) will be usedherein. The agents include, but are not limited to, polypeptides such asantibodies that specifically bind ILT2, ILT4, or both ILT2 and ILT4.Generally, the agents referred to herein as “ILT-bindingagents”encompass ILT2-binding agents, ILT4-binding agents, and agentsbinding to both ILT2 and ILT4 (referred to as “ILT2/ILT4-bindingagents”). In some embodiments, an ILT-binding agent inhibits ILT2 and/orILT4 activity. In some embodiments, an ILT-binding agent enhances animmune response. In some embodiments, an ILT-binding agent reversessuppression of an immune cell activity. The disclosure provides methodsof using an ILT-binding agent, for example, in treating cancer (e.g., anadvanced solid tumor). In some embodiments, an ILT-binding agent is usedin combination therapy in, for example, treating cancer. In someembodiments, an ILT-binding agent is used in combination with at leastone additional therapeutic agent in, for example, treating cancer.

In some instances, the ILT-binding agents described herein have one ormore (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or more) of the followingproperties in any combination or permutation:

(1) binds human ILT2;

(2) binds human ILT4;

(3) binds rhesus ILT2;

(4) binds cyno ILT2;

(5) does not bind ILT3, ILT5, and LILRB5;

(6) does not bind LILRA2, LILRA4, LILRAS, and LILRA6;

(7) is an ILT2 antagonist;

(8) is an ILT4 antagonist,

(9) inhibits ILT2 activity;

(10) inhibits ILT4 activity;

(11) inhibits ILT2 signaling in cells that express ILT2;

(12) inhibits ILT4 signaling in cells that express ILT4;

(13) inhibits binding of ILT2 to MHC I molecules;

(14) inhibits binding of ILT4 to MHC I molecules;

(15) inhibits ILT2-induced suppression of myeloid cells;

(16) inhibits ILT4-induced suppression of myeloid cells;

(17) inhibits ILT2-induced suppression of myeloid cell activity;

(18) inhibits ILT4-induced suppression of myeloid cell activity;

(19) restores FcR activation in myeloid cells;

(20) enhances NK cell activity;

(21) enhances cytotoxic T lymphocyte (CTL) activity;

(22) enhances macrophage phagocytosis; and

(23) inhibits MDSC mediated suppression of immune cells.

The disclosure also provides compositions comprising the ILT-bindingagents described herein. In some embodiments, the disclosure providespharmaceutical compositions comprising the ILT-binding agents and apharmaceutically acceptable carrier. Polynucleotides and/or vectorsencoding the ILT-binding agents are provided. Cells comprising thepolynucleotides and/or the vectors described herein are also provided.Cells comprising or producing the ILT-binding agents described hereinare provided. Methods of making the ILT-binding agents described hereinare also provided.

In one aspect, the present disclosure provides ILT-binding agents thatbind ILT2. In some embodiments, ILT-binding agents bind human ILT2. Insome embodiments, the ILT-binding agents bind rhesus monkey (“rhesus”)ILT2. In some embodiments, the ILT-binding agents cynomolgus monkey(“cyno”) ILT2. In some embodiments, the ILT-binding agents bind humanILT2 and rhesus ILT2. In some embodiments, the ILT-binding agents bindhuman ILT2 and cyno ILT2. In some embodiments, the ILT-binding agentsbind human ILT2, rhesus ILT2, and cyno ILT2. In some embodiments, theILT-binding agents bind SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ IDNO:4, SEQ ID NO:5, SEQ ID NO:6, and/or SEQ ID NO:7. In some embodiments,the ILT-binding agents bind SEQ ID NO:15, SEQ ID NO:16, SEQ ID NO:17,SEQ ID NO:18, SEQ ID NO:19, SEQ ID NO:20, and/or SEQ ID NO:21. In someembodiments, the ILT-binding agents bind SEQ ID NO:166, SEQ ID NO:167,SEQ ID NO:168, SEQ ID NO:169, SEQ ID NO:170, SEQ ID NO:171, and/or SEQID NO:172. In some embodiments, the ILT-binding agents are antibodies.In some embodiments, the ILT-binding agents are antibody fragments.

In some embodiments, the ILT-binding agents bind within theextracellular domain of ILT2. In some embodiments, the ILT-bindingagents bind SEQ ID NO:3. In some embodiments, the ILT-binding agentsbind within amino acids 24-461 of SEQ ID NO:1. In some embodiments, theILT-binding agents bind within amino acids 27-115 of SEQ ID NO:1. Insome embodiments, the ILT-binding agents bind within amino acids 116-221of SEQ ID NO:1. In some embodiments, the ILT-binding agents bind withinamino acids 222-312 of SEQ ID NO:1. In some embodiments, the ILT-bindingagents bind within amino acids 313-409 of SEQ ID NO:1. In someembodiments, the ILT-binding agents bind within amino acids 27-221 ofSEQ ID NO:1. In some embodiments, the ILT-binding agents bind withinamino acids 116-312 of SEQ ID NO:1. In some embodiments, the ILT-bindingagents bind within amino acids 222-409 of SEQ ID NO:1. In someembodiments, the ILT-binding agents bind a conformational epitope withinthe extracellular domain of ILT2. In some embodiments, the ILT-bindingagents bind a conformational epitope within one of the Ig-like C2-typedomains of ILT2 (e.g., D1, D2, D3, or D4). In some embodiments, theILT-binding agents bind a conformational epitope within two or more ofthe Ig-like C2-type domains of ILT2 (D1, D2, D3, and/or D4). In someembodiments, the ILT-binding agents bind a conformational epitope withinthe D4-stem region of ILT2.

In another aspect, the present disclosure provides ILT-binding agentsthat bind ILT4. In some embodiments, the ILT-binding agents bind humanILT4. In some embodiments, the ILT-binding agents bind SEQ ID NO:8, SEQID NO:9, SEQ ID NO:10, SEQ ID NO:11, SEQ ID NO:12, SEQ ID NO:13, and/orSEQ ID NO:14. In some embodiments, the ILT-binding agents areantibodies. In some embodiments, the ILT-binding agents are antibodyfragments.

In some embodiments, the ILT-binding agents bind within theextracellular domain of ILT4. In some embodiments, an agent binds SEQ IDNO:10. In some embodiments, ILT-binding agents bind within amino acids22-461 of SEQ ID NO:8. In some embodiments, ILT-binding agents bindwithin amino acids 27-110 of SEQ ID NO:8. In some embodiments,ILT-binding agents bind within amino acids 111-229 of SEQ ID NO:8. Insome embodiments, ILT-binding agents bind within amino acids 230-318 ofSEQ ID NO:8. In some embodiments, ILT-binding agents bind within aminoacids 330-419 of SEQ ID NO:8. In some embodiments, ILT-binding agentsbind within amino acids 27-229 of SEQ ID NO:8. In some embodiments,ILT-binding agents bind within amino acids 111-318 of SEQ ID NO:8. Insome embodiments, ILT-binding agents bind within amino acids 230-419 ofSEQ ID NO:8. In some embodiments, ILT-binding agents bind aconformational epitope within the extracellular domain of ILT4. In someembodiments, ILT-binding agents bind a conformational epitope within oneof the Ig-like C2-type domains of ILT4 (e.g., D1, D2, D3, or D4). Insome embodiments, ILT-binding agents bind a conformational epitopewithin two or more of the Ig-like C2-type domains of ILT4 (D1, D2, D3,and/or D4). In some embodiments, ILT-binding agents bind aconformational epitope within the D4-stem region of ILT4.

In one aspect, the present disclosure provides ILT-binding agents thatbind human ILT2, human ILT4, or both human ILT2 and ILT4 and have atleast one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, or 19) of the following properties: (1) binds rhesusILT2; (2) binds cyno ILT2; (3) does not bind ILT3, ILT5, and LILRB5; (4)does not bind LILRA2, LILRA4, LILRA5, and LILRA6; (5) is an ILT2antagonist; (6) is an ILT4 antagonist, (7) inhibits ILT2 activity; (8)inhibits ILT4 activity; (9) inhibits ILT2 signaling in cells thatexpress ILT2; (10) inhibits ILT4 signaling in cells that express ILT4;(11) inhibits binding of ILT2 to one or more MHC I molecules; (12)inhibits binding of ILT4 to one or more MHC I molecules; (13) inhibitsILT2-induced suppression of myeloid cells; (14) inhibits ILT4-inducedsuppression of myeloid cells; (15) inhibits ILT2-induced suppression ofmyeloid cell activity; (16) inhibits ILT4-induced suppression of myeloidcell activity; (17) restores FcR activation in myeloid cells; (18)enhances NK cell activity; and/or (19) enhances CTL activity. In someembodiments, the myeloid cells are monocytes. In some embodiments, themyeloid cells are macrophages. In some embodiments, the myeloid cellsare dendritic cells. In some embodiments, the myeloid cells aretolerogenic dendritic cells. In some embodiments, the myeloid cells areantigen-presenting cells (APCs). In some embodiments, the MHC I moleculeis HLA-A, HLA-B, HLA-C, HLA-E, and/or HLA-G.

In one aspect, the present disclosure provides agents that specificallybind human ILT2. In some embodiments, the present disclosure provides anILT2-binding agent, wherein the binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFSLTNYGVS (SEQ ID NO:22), a heavychain variable region CDR2 comprising the amino acid sequenceIIWGDGSTNYHSALIS (SEQ ID NO:23), and a heavy chain variable region CDR3comprising the amino acid sequence PNWDTYAMDF (SEQ ID NO:24), and/or (b)a light chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASQDISNFLN (SEQ ID NO:25), alight chain variable region CDR2 comprising the amino acid sequenceCTSKLHS (SEQ ID NO:26), and a light chain variable region CDR3comprising the amino acid sequence QQGNTLPPT (SEQ ID NO:27). The presentdisclosure also provides an ILT2-binding agent that comprises the sixCDRs of any of the CDR definitions provided in Table 1.

In some embodiments, an ILT2-binding agent comprises: (a) a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:125;and/or (b) a light chain variable region having at least 80% sequenceidentity to SEQ ID NO:126. In some embodiments, an ILT2-binding agentcomprises a heavy chain variable region having at least 80%, at least85%, at least 90%, at least 95%, at least 96%, at least 97%, at least98%, or at least 99% sequence identity to SEQ ID NO:125 and/or a lightchain variable region having at least 80%, at least 85%, at least 90%,at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:126. In some embodiments, an ILT2-bindingagent comprises a heavy chain variable region of SEQ ID NO:125 and/or alight chain variable region of SEQ ID NO:126. In some embodiments, theILT2-binding agent comprises a heavy chain variable region of SEQ IDNO:125 and a light chain variable region of SEQ ID NO:126.

In some embodiments, an ILT2-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:125 and a light chain variable region CDR1, CDR2, and CDR3 fromthe amino acid sequence of SEQ ID NO:126. In some embodiments, anILT2-binding agent comprises a heavy chain variable region comprising aheavy chain variable region CDR1, CDR2, and CDR3 from the amino acidsequence of SEQ ID NO:125 and a light chain variable region comprising alight chain variable region CDR1, CDR2, and CDR3 from the amino acidsequence of SEQ ID NO:126.

In some embodiments, an ILT4-binding agent comprises (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYSFTGYYMH (SEQ ID NO:38), a heavy chainvariable region CDR2 comprising the amino acid sequenceRVYPNNGDTSYNQKFKV (SEQ ID NO:39), and a heavy chain variable region CDR3comprising the amino acid sequence GATVVESLFAY (SEQ ID NO:40), and/or(b) a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence RASESVDNYGNNFLH (SEQ IDNO:41), a light chain variable region CDR2 comprising the amino acidsequence RTSNLES (SEQ ID NO:42), and a light chain variable region CDR3comprising the amino acid sequence QQSNEDPYT (SEQ ID NO:43). The presentdisclosure also provides an ILT2-binding agent that comprises the sixCDRs of any of the CDR definitions provided in Table 2.

In some embodiments, an ILT4-binding agent comprises: (a) a heavy chainvariable region having at least 80% identity to SEQ ID NO:127 and/or (b)a light chain variable region having at least 80% identity to SEQ IDNO:128. In some embodiments, an ILT4-binding agent comprises a heavychain variable region having at least 80%, at least 85%, at least 90%,at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:127 and/or a light chain variable regionhaving at least 80%, at least 85%, at least 90%, at least 95%, at least96%, at least 97%, at least 98%, or at least 99% sequence identity toSEQ ID NO:128. In some embodiments, an ILT4-binding agent comprises aheavy chain variable region of SEQ ID NO:127 and/or a light chainvariable region of SEQ ID NO:128. In some embodiments, the ILT4-bindingagent comprises a heavy chain variable region of SEQ ID NO:127 and alight chain variable region of SEQ ID NO:128.

In some embodiments, an ILT4-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:127 and/or a light chain variable region CDR1, CDR2, and CDR3 fromthe amino acid sequence of SEQ ID NO:128. In some embodiments, anILT4-binding agent comprises a heavy chain variable region comprising aheavy chain variable region CDR1, CDR2, and CDR3 from the amino acidsequence of SEQ ID NO:127 and/or a light chain variable regioncomprising a light chain variable region CDR1, CDR2, and CDR3 from theamino acid sequence of SEQ ID NO:128.

In some embodiments, an ILT4-binding agent comprises (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYTFTNYGMN (SEQ ID NO:54), a heavy chainvariable region CDR2 comprising the amino acid sequenceWINTYIGEPIYADDFKG (SEQ ID NO:55), and a heavy chain variable region CDR3comprising the amino acid sequence RSDYDGYAMDY (SEQ ID NO:56), and/or(b) a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence KSSQSLLYSGNQKNYLA (SEQ IDNO:57), a light chain variable region CDR2 comprising the amino acidsequence WASTRES (SEQ ID NO:58), and a light chain variable region CDR3comprising the amino acid sequence QQHDSYPT (SEQ ID NO:59). The presentdisclosure also provides an ILT2-binding agent that comprises the sixCDRs of any of the CDR definitions provided in Table 3.

In some embodiments, an ILT4-binding agent comprises: (a) a heavy chainvariable region having at least 80% identity to SEQ ID NO:129 and/or (b)a light chain variable region having at least 80% identity to SEQ IDNO:130. In some embodiments, an ILT4-binding agent comprises a heavychain variable region having at least 80%, at least 85%, at least 90%,at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:129 and/or a light chain variable regionhaving at least 80%, at least 85%, at least 90%, at least 95%, at least96%, at least 97%, at least 98%, or at least 99% sequence identity toSEQ ID NO:130. In some embodiments, an ILT4-binding agent comprises aheavy chain variable region of SEQ ID NO:129 and/or a light chainvariable region of SEQ ID NO:130. In some embodiments, the ILT4-bindingagent comprises a heavy chain variable region of SEQ ID NO:129 and alight chain variable region of SEQ ID NO:130.

In some embodiments, an ILT4-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:129 and/or a light chain variable region CDR1, CDR2, and CDR3 fromthe amino acid sequence of SEQ ID NO:130. In some embodiments, anILT4-binding agent comprises a heavy chain variable region comprising aheavy chain variable region CDR1, CDR2, and CDR3 from the amino acidsequence of SEQ ID NO:129 and/or a light chain variable regioncomprising a light chain variable region CDR1, CDR2, and CDR3 from theamino acid sequence of SEQ ID NO:130.

In some embodiments, an ILT2/ILT4-binding agent comprises (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavychain variable region CDR2 comprising the amino acid sequenceDFNPNNGGTTYNQKFEG (SEQ ID NO:71) or DFNPNNAGTTYNQKFEG (SEQ ID NO:118),and a heavy chain variable region CDR3 comprising the amino acidsequence GRFYYGSLYSFDY (SEQ ID NO:72), and/or (b) a light chain variableregion comprising a light chain variable region CDR1 comprising theamino acid sequence RASGNIHNYLA (SEQ ID NO:73), a light chain variableregion CDR2 comprising the amino acid sequence NAKTLAD (SEQ ID NO:74),and a light chain variable region CDR3 comprising the amino acidsequence QHFWTSIT (SEQ ID NO:75). The present disclosure also providesan ILT2/ILT4 binding agent that comprises the six CDRs of any of the CDRdefinitions provided in Tables 4A and 4B.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region having at least 80% identity to SEQ ID NO:131and/or (b) a light chain variable region having at least 80% identity toSEQ ID NO:132. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain variable region having at least 80%, at least 85%, atleast 90%, at least 95%, at least 96%, at least 97%, at least 98%, or atleast 99% sequence identity to SEQ ID NO:131 and/or a light chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:132. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region of SEQID NO:131 and/or a light chain variable region of SEQ ID NO:132. In someembodiments, the ILT2/ILT4-binding agent comprises a heavy chainvariable region of SEQ ID NO:131 and a light chain variable region ofSEQ ID NO:132.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region having at least 80% identity to SEQ ID NO:133and/or (b) a light chain variable region having at least 80% identity toSEQ ID NO:134. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain variable region having at least 80%, at least 85%, atleast 90%, at least 95%, at least 96%, at least 97%, at least 98%, or atleast 99% sequence identity to SEQ ID NO:133 and/or a light chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:134. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region of SEQID NO:133 and/or a light chain variable region of SEQ ID NO:134. In someembodiments, the ILT2/ILT4-binding agent comprises a heavy chainvariable region of SEQ ID NO:133 and a light chain variable region ofSEQ ID NO:134.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:131 and/or a light chain variable region CDR1, CDR2, and CDR3 fromthe amino acid sequence of SEQ ID NO:132. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable regioncomprising a heavy chain variable region CDR1, CDR2, and CDR3 from theamino acid sequence of SEQ ID NO:131 and/or a light chain variableregion comprising a light chain variable region CDR1, CDR2, and CDR3from the amino acid sequence of SEQ ID NO:132. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region CDR1,CDR2, and CDR3 from the amino acid sequence of SEQ ID NO:133 and/or alight chain variable region CDR1, CDR2, and CDR3 from the amino acidsequence of SEQ ID NO:134. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:133 and/or a light chain variable region comprising a light chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:134.

In some embodiments, an ILT2/ILT4-binding agent comprises (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavychain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYGTMYYYAMDY (SEQ ID NO:88),and/or (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). Thepresent disclosure also provides an ILT2/ILT4 binding agent thatcomprises the six CDRs of any of the CDR definitions provided in Table5.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region having at least 80% identity to SEQ ID NO:135and/or (b) a light chain variable region having at least 80% identity toSEQ ID NO:136. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain variable region having at least 80%, at least 85%, atleast 90%, at least 95%, at least 96%, at least 97%, at least 98%, or atleast 99% sequence identity to SEQ ID NO:135 and/or a light chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:136. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region of SEQID NO:135 and/or a light chain variable region of SEQ ID NO:136. In someembodiments, the ILT2/ILT4-binding agent comprises a heavy chainvariable region of SEQ ID NO:135 and a light chain variable region ofSEQ ID NO:136.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:135 and/or a light chain variable region CDR1, CDR2, and CDR3 fromthe amino acid sequence of SEQ ID NO:136. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable regioncomprising a heavy chain variable region CDR1, CDR2, and CDR3 from theamino acid sequence of SEQ ID NO:135 and/or a light chain variableregion comprising a light chain variable region CDR1, CDR2, and CDR3from the amino acid sequence of SEQ ID NO:136.

In some embodiments, an ILT2/ILT4-binding agent comprises (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavychain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYDTMYYYAMDY (SEQ IDNO:102), and/or (b) a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFIY (SEQ ID NO:103), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91). The present disclosure also provides an ILT2/ILT4binding agent that comprises the six CDRs of any of the CDR definitionsprovided in Tables 6A and 6B.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region having at least 80% identity to SEQ ID NO:137and/or (b) a light chain variable region having at least 80% identity toSEQ ID NO:138. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain variable region having at least 80%, at least 85%, atleast 90%, at least 95%, at least 96%, at least 97%, at least 98%, or atleast 99% sequence identity to SEQ ID NO:137 and/or a light chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:138. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region of SEQID NO:137 and/or a light chain variable region of SEQ ID NO:138. In someembodiments, the ILT2/ILT4-binding agent comprises a heavy chainvariable region of SEQ ID NO:137 and a light chain variable region ofSEQ ID NO:138.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region having at least 80% identity to SEQ ID NO:139and/or (b) a light chain variable region having at least 80% identity toSEQ ID NO:140. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain variable region having at least 80%, at least 85%, atleast 90%, at least 95%, at least 96%, at least 97%, at least 98%, or atleast 99% sequence identity to SEQ ID NO:139 and/or a light chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:140. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region of SEQID NO:139 and/or a light chain variable region of SEQ ID NO:140. In someembodiments, the ILT2/ILT4-binding agent comprises a heavy chainvariable region of SEQ ID NO:139 and a light chain variable region ofSEQ ID NO:140.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:137 and/or a light chain variable region CDR1, CDR2, and CDR3 fromthe amino acid sequence of SEQ ID NO:138. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable regioncomprising a heavy chain variable region CDR1, CDR2, and CDR3 from theamino acid sequence of SEQ ID NO:137 and/or a light chain variableregion comprising a light chain variable region CDR1, CDR2, and CDR3from the amino acid sequence of SEQ ID NO:138. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region CDR1,CDR2, and CDR3 from the amino acid sequence of SEQ ID NO:139 and/or alight chain variable region CDR1, CDR2, and CDR3 from the amino acidsequence of SEQ ID NO:140. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:139 and/or a light chain variable region comprising a light chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:140.

In some embodiments, an ILT2/ILT4-binding agent comprises (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavychain variable region CDR2 comprising the amino acid sequenceNVNPNNGGTSYNQKFKG (SEQ ID NO:106), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and/or (b) a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91). The present disclosure also provides an ILT2/ILT4binding agent that comprises the six CDRs of any of the CDR definitionsprovided in Table 7.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region having at least 80% identity to SEQ ID NO:141and/or (b) a light chain variable region having at least 80% identity toSEQ ID NO:142. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain variable region having at least 80%, at least 85%, atleast 90%, at least 95%, at least 96%, at least 97%, at least 98%, or atleast 99% sequence identity to SEQ ID NO:141 and/or a light chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:142. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region of SEQID NO:141 and/or a light chain variable region of SEQ ID NO:142. In someembodiments, the ILT2/ILT4-binding agent comprises a heavy chainvariable region of SEQ ID NO:141 and a light chain variable region ofSEQ ID NO:142.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:141 and/or a light chain variable region CDR1, CDR2, and CDR3 fromthe amino acid sequence of SEQ ID NO:142. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable regioncomprising a heavy chain variable region CDR1, CDR2, and CDR3 from theamino acid sequence of SEQ ID NO:141 and/or a light chain variableregion comprising a light chain variable region CDR1, CDR2, and CDR3from the amino acid sequence of SEQ ID NO:142.

In some embodiments, an ILT2/ILT4-binding agent comprises (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYIN (SEQ ID NO:111), a heavychain variable region CDR2 comprising the amino acid sequenceNVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and/or (b) a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91). The present disclosure also provides an ILT2/ILT4binding agent that comprises the six CDRs of any of the CDR definitionsprovided in Tables 8A and 8B.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region having at least 80% identity to SEQ ID NO:143and/or (b) a light chain variable region having at least 80% identity toSEQ ID NO:142. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain variable region having at least 80%, at least 85%, atleast 90%, at least 95%, at least 96%, at least 97%, at least 98%, or atleast 99% sequence identity to SEQ ID NO:143 and/or a light chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:142. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region of SEQID NO:143 and/or a light chain variable region of SEQ ID NO:142. In someembodiments, the ILT2/ILT4-binding agent comprises a heavy chainvariable region of SEQ ID NO:143 and a light chain variable region ofSEQ ID NO:142.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region having at least 80% identity to SEQ ID NO:144and/or (b) a light chain variable region having at least 80% identity toSEQ ID NO:145. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain variable region having at least 80%, at least 85%, atleast 90%, at least 95%, at least 96%, at least 97%, at least 98%, or atleast 99% sequence identity to SEQ ID NO:144 and/or a light chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 96%, at least 97%, at least 98%, or at least 99%sequence identity to SEQ ID NO:145. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region of SEQID NO:144 and/or a light chain variable region of SEQ ID NO:145. In someembodiments, the ILT2/ILT4-binding agent comprises a heavy chainvariable region of SEQ ID NO:144 and a light chain variable region ofSEQ ID NO:145.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:143 and/or a light chain variable region CDR1, CDR2, and CDR3 fromthe amino acid sequence of SEQ ID NO:142. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable regioncomprising a heavy chain variable region CDR1, CDR2, and CDR3 from theamino acid sequence of SEQ ID NO:143 and/or a light chain variableregion comprising a light chain variable region CDR1, CDR2, and CDR3from the amino acid sequence of SEQ ID NO:142. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region CDR1,CDR2, and CDR3 from the amino acid sequence of SEQ ID NO:144 and/or alight chain variable region CDR1, CDR2, and CDR3 from the amino acidsequence of SEQ ID NO:145. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising a heavy chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:144 and/or a light chain variable region comprising a light chainvariable region CDR1, CDR2, and CDR3 from the amino acid sequence of SEQID NO:145.

In another aspect of the disclosure, provided herein is an agent thatcompetes for binding to ILT2, ILT4, or ILT2/ILT4 with any of theILT-binding agents described herein. In some embodiments, the agentcompetes for binding to both human ILT2 and human ILT4 with any of theILT-binding agents described herein. In some embodiments, the agentcompetes for binding to human ILT2 with any of the ILT-binding agentsdescribed herein. In some embodiments, the agent competes for binding tohuman ILT4 with any of the ILT-binding agents described herein. In someembodiments, the agent is antibody. In some embodiment, the agent is anantibody fragment.

In some embodiments of each of the aforementioned aspects andembodiments, as well as other aspects and embodiments described herein,the ILT-binding agents are antibodies. In some embodiments, theantibodies are recombinant antibodies. In some embodiments, theantibodies are humanized antibodies. In some embodiments, the antibodiesare human antibodies. In some embodiments, the antibody are chimericantibodies. In some embodiments, the antibody are whole or intactantibodies. In some embodiments, the antibodiesare bispecific antibodiesor a multispecific antibodies. In some embodiments, the antibodies areantibody fragments comprising at least one antigen-binding site. In someembodiments, the antibodies are a Fab, Fab′, F(ab′)₂, Fv, scFv, (scFv)₂,single chain antibody, dual variable region antibody, single variableregion antibody, linear antibody, diabody, nanobody, or a V regionantibody. In some embodiments, the antibodies are IgG antibodies. Insome embodiments, the antibodies are IgG1 antibodies, IgG2 antibodies,IgG3 antibodies, or IgG4 antibodies. In some embodiments, the antibodieseach comprises a kappa light chain. In some embodiments, the antibodieseach comprises a lambda light chain. In some instances, the antibodieseach comprises a human IgG1 constant region. In some instances, theantibodies each comprises a human kappa light chain constant region. Insome instances, the antibodies each comprises a human IgG1 constantregion and a human kappa light chain constant region. In certaininstances, the human IgG1 constant region comprises one or moremutations that reduce or eliminate Fc effector functions. In certaininstances, the human IgG1 constant region comprises a N297G mutationthat reduces effector function.

In some embodiments of each of the aforementioned aspects andembodiments, as well as other aspects and embodiments describedherein,the ILT-binding agents each is attached (either directly orindirectly) to a half-life extending moiety.

In some embodiments of each of the aforementioned aspects andembodiments, as well as other aspects and embodiments described herein,the ILT-binding agents described herein are antagonists of ILT2. In someembodiments, the ILT-binding agents inhibit ILT2 activity. In someembodiments, the ILT-binding agents are antagonistic antibodies. In someembodiments, the ILT-binding agents are antibodies that inhibitILT2-induced immune cell suppression. In some embodiments, theILT-binding agents are antibodies that inhibit ILT2-induced myeloid cellsuppression.

In some embodiments of each of the aforementioned aspects andembodiments, as well as other aspects and embodiments described herein,the ILT-binding agents described herein are antagonists of ILT4. In someembodiments, the ILT-binding agents inhibit ILT4 activity. In someembodiments, the ILT-binding agents are antagonistic antibodies. In someembodiments, the ILT-binding agents are antibodies that inhibitILT4-induced immune cell suppression. In some embodiments, theILT-binding agents are antibodies that inhibit ILT4-induced myeloid cellsuppression.

In some embodiments of each of the aforementioned aspects andembodiments, as well as other aspects and embodiments described herein,the ILT-binding agents described herein are antagonists of human ILT2and ILT4. In some embodiments, the ILT-binding agents inhibit ILT2activity and ILT4 activity. In some embodiments, the ILT-binding agentsare antagonistic antibodies. In some embodiments, the ILT-binding agentsare antibodies that inhibit ILT2-induced and ILT4-induced immune cellsuppression. In some embodiments, the ILT-binding agents are antibodiesthat inhibit ILT2-induced and ILT4-induced myeloid cell suppression.

In some embodiments, the ILT-binding agents are antibodies thatreactivate tolerogenic dendritic cells. In some embodiments, theILT-binding agents are antibodies that inhibit the activity ofmyeloid-derived suppressor cells (MDSCs). In some embodiments, theILT-binding agents are antibodies that enhance cytolytic T-celllymphocyte (CTL) activity. In some embodiments, the ILT-binding agentsare antibodies that enhances CD8+ T -cell cytolytic activity. In someembodiments, the ILT-binding agents are antibodies that enhance naturalkiller (NK) cell activity. In some embodiments, the ILT-binding agentsare antibodies that enhance macrophage phagocytosis. In someembodiments, the ILT-binding agents desuppress or activate Fc receptorsignaling in myeloid cells. In some embodiments, the ILT-binding agentsact synergistically with an immune checkpoint inhibitor.

In another aspect, the disclosure provides compositions comprising anILT-binding agent described herein. In some embodiments, a compositioncomprises an anti-ILT antibody described herein. In some embodiments, acomposition comprises a recombinant anti-ILT antibody described herein.In some embodiments, a composition comprises the anti-ILT2 antibody27F9. In some embodiments, a composition comprises the anti-ILT4antibody 47C8 or antibody 48A5. In some embodiments, a compositioncomprises an anti-ILT2/ILT4 antibody selected from the group consistingof: 47H6, Hz47H6.v2, 51A1, 64A12, Hz64A12, 73C4, 73D1, and Hz73D1.v1.

In some instances, pharmaceutical compositions are provided, whichcomprise (a) a means for inhibiting the interaction between ILT2 and/orILT4 and MHC Class I (e.g., on tumor cells); and (b) a pharmaceuticallyacceptable carrier. In some embodiments, the means for inhibiting theinteraction between ILT2 and/or ILT4 and MHC Class I comprises anantibody comprising a heavy chain variable region comprising VH-CDR1,VH-CDR2, and VH-CDR3 and a light chain variable region comprisingVL-CDR1, VL-CDR2, and VL-CDR3 from any one of 27F9, 47C8, 48A5, 47H6,Hz47H6.v2, 51A1, 64A12, Hz64A12, 73C4, 73D1, and Hz73D1.v1.

In some embodiments of each of the aforementioned aspects, as well asother aspects and/or embodiments described elsewhere herein, theILT-binding agent is isolated. In some embodiments, the ILT-bindingagent is substantially pure.

In another aspect, the disclosure provides polynucleotides comprising apolynucleotide that encodes an ILT-binding agent described herein. Insome embodiments, a polynucleotide encodes an anti-ILT2 antibodydescribed herein. In some embodiments, a polynucleotide encodes ananti-ILT4 antibody described herein. In some embodiments, apolynucleotide encodes an anti-ILT2/ILT4 antibody described herein. Insome embodiments, the polynucleotide is isolated. In some embodiments, avector comprises a polynucleotide that encodes an ILT-binding agentdescribed herein. In some embodiments, an isolated cell comprises apolynucleotide that encodes an ILT-binding agent described herein. Insome embodiments, an isolated cell comprises a vector comprising apolynucleotide that encodes an ILT-binding agent described herein. Insome embodiments, a cell comprises an ILT-binding agent describedherein. In some embodiments, a cell produces an ILT-binding agentdescribed herein. In some embodiments, a cell produces an anti-ILTantibody described herein. In some embodiments, a cell is a monoclonalcell line. In some embodiments, a cell is a hybridoma.

In another aspect, the disclosure provides methods of using theILT-binding agents described herein. In some embodiments, the methodscomprise using a composition comprising an ILT2-binding agent describedherein. In some embodiments, the methods comprise using a compositioncomprising an ILT4-binding agent described herein. In some embodiments,the methods comprise using a composition comprising an ILT2/ILT4-bindingagent described herein. In some embodiments, the methods comprise usinga pharmaceutical composition comprising an ILT2-binding agent describedherein. In some embodiments, the methods comprise using a pharmaceuticalcomposition comprising an ILT4-binding agent described herein. In someembodiments, the methods comprise using a pharmaceutical compositioncomprising an ILT2/ILT4-binding agent described herein.

In some embodiments, a method of disrupting, inhibiting, or blocking thebinding of ILT2 and/or ILT4 to a ligand and/or binding partner isprovided. In some embodiments, a method of disrupting, inhibiting, orblocking the binding of ILT2 and/or ILT4 to one or more MHC I moleculesis provided. In some embodiments, a method of disrupting, inhibiting, orblocking the binding of ILT2 and/or ILT4 to a MHC I molecule in amixture of cells comprises contacting the cells with an ILT2-bindingagent, an ILT4-binding agent, or an ILT2/ILT4-binding agent describedherein.

In some embodiments, a method of disrupting, inhibiting, or blockingILT2 and/or ILT4 activity is provided. In some embodiments, a method ofdisrupting, inhibiting, or blocking ILT2 activity in a mixture of cellscomprises contacting the cells with an ILT2-binding agent or anILT2/ILT4-binding agent described herein. In some embodiments, a methodof disrupting, inhibiting, or blocking ILT4 activity in a mixture ofcells comprises contacting the cells with an ILT4-binding agent or anILT2/ILT4-binding agent described herein. In some embodiments, a methodof disrupting, inhibiting, or blocking ILT2 and ILT4 activity in amixture of cells comprises contacting the cells with anILT2/ILT4-binding agent described herein.

In some embodiments, a method of disrupting, inhibiting, or blocking MHCI-induced ILT2 and/or ILT4 activity is provided. In some embodiments, amethod of disrupting, inhibiting, or blocking MHC I-induced ILT2activity in a mixture of cells comprises contacting the cells with anILT2-binding agent or an ILT2/ILT4-binding agent described herein. Insome embodiments, a method of disrupting, inhibiting, or blocking MHCI-induced ILT4 activity in a mixture of cells comprises contacting thecells with an ILT4-binding agent or an ILT2/ILT4-binding agent describedherein. In some embodiments, a method of disrupting, inhibiting, orblocking MHC I-induced ILT2 and ILT4 activity in a mixture of cellscomprises contacting the cells with an ILT2/ILT4-binding agent describedherein. In some embodiments, the MHC I molecule is HLA-A, HLA-B, HLA-C,HLA-E, and/or HLA-G.

In some embodiments, a method of disrupting, inhibiting, or blockingILT2-induced and/or ILT4-induced suppression of myeloid cells isprovided. In some embodiments, a method of disrupting, inhibiting, orblocking ILT2-induced and/or ILT4-induced suppression of myeloid cellscomprises contacting the myeloid cells with an ILT2-binding agent, anILT4-binding agent, or an ILT2/ILT4-binding agent described herein. Insome embodiments, a method of disrupting, inhibiting, or blockingILT2-induced suppression of myeloid cells comprises contacting themyeloid cells with an ILT2-binding agent or an ILT2/ILT4-binding agentdescribed herein. In some embodiments, a method of disrupting,inhibiting, or blocking ILT4-induced suppression of myeloid cellscomprises contacting the myeloid cells with an ILT4-binding agent or anILT2/ILT4-binding agent described herein. In some embodiments, a methodof disrupting, inhibiting, or blocking ILT2-induced and ILT4-inducedsuppression of myeloid cells comprises contacting the myeloid cells withan ILT2/ILT4-binding agent described herein.

In some embodiments, a method of disrupting, inhibiting, or blockingILT2-induced and/or ILT4-induced suppression of myeloid cell activitycomprises contacting the myeloid cell with an ILT2-binding agent, anILT4-binding agent, or an ILT2/ILT4-binding agent described herein. Insome embodiments, a method of disrupting, inhibiting, or blockingILT2-induced or ILT4-induced suppression of myeloid cell activitycomprises contacting the myeloid cell with an ILT2/ILT4-binding agentdescribed herein. In some embodiments, a method of disrupting,inhibiting, or blocking ILT2-induced and/or ILT4-induced suppression ofmyeloid cell activity restores FcR activity in myeloid cells. In someembodiments, a method of disrupting, inhibiting, or blockingILT2-induced and/or ILT4-induced suppression of myeloid activityenhances, increases, or restores chemokine/cytokine production inmyeloid cells. In some embodiments, a method of disrupting, inhibiting,or blocking ILT2-induced and/or ILT4-induced suppression of myeloid cellactivity enhances, increases, or restores myeloid cell proliferationactivity. In some embodiments, a method of disrupting, inhibiting, orblocking ILT2-induced and/or ILT4-induced suppression of myeloid cellactivity enhances, increases, or restores phagocytic activity of themyeloid cell. In some embodiments, the myeloid cells are monocytes. Insome embodiments, the myeloid cells are macrophages. In someembodiments, the myeloid cells are dendritic cells. In some embodiments,the myeloid cells are tolerogenic dendritic cells. In some embodiments,the myeloid cells are APCs.

In some embodiments, a method of enhancing or increasing NK cellactivity is provided. In some embodiments, a method of enhancing orincreasing NK cell activity comprises contacting the NK cell with anILT2-binding agent, or an ILT2/ILT4-binding agent described herein. Insome embodiments, a method of enhancing or increasing NK cell activitycomprises contacting the NK cell with an ILT2/ILT4-binding agentdescribed herein.

In some embodiments, a method of enhancing or increasing cytotoxic Tlymphocyte (CTL) activity is provided. In some embodiments, a method ofenhancing or increasing CTL activity comprises contacting the CTL withan ILT2-binding agent, or an ILT2/ILT4-binding agent described herein.In some embodiments, a method of enhancing or increasing CTL activitycomprises contacting the CTL with an ILT2/ILT4-binding agent describedherein.

In some embodiments, a method of enhancing or increasing macrophagephagocytosis is provided. In some embodiments, a method of enhancing orincreasing phagocytosis comprises contacting the macrophage with anILT2-binding agent, or an ILT2/ILT4-binding agent described herein. Insome embodiments, a method of enhancing or increasing phagocytosiscomprises contacting the macrophage with an ILT2/ILT4-binding agentdescribed herein.

In some embodiments, a method of inhibiting the activity ofmyeloid-derived suppressor cells (MDSCs) is provided. In someembodiments, a method of inhibiting the activity of MDSCs comprisescontacting the MDSCs with an ILT4-binding agent, or an ILT2/ILT4-bindingagent described herein. In some embodiments, a method inhibiting theactivity of MDSCs comprises contacting the MDSCs with anILT2/ILT4-binding agent described herein.

In some embodiments of each of the aforementioned aspects andembodiments, as well as other aspects and embodiments described herein,the methods can be in vitro, ex vivo, or in vivo.

In some embodiments, a method of disrupting, inhibiting, or blocking thebinding of ILT2 or ILT4 to a MHC I molecule in a subject, comprisesadministering to the subject an effective amount of an ILT2-bindingagent, an ILT4-binding agent, or an ILT2/ILT4-binding agent describedherein. In some embodiments, a method of disrupting, inhibiting, orblocking the binding of ILT2 or ILT4 to a MHC I molecule in a subject,comprises administering to the subject an effective amount of anILT2/ILT4-binding agent described herein. In some embodiments of themethods described herein, the MHC I molecule is HLA-A, HLA-B, HLA-C,HLA-E, and/or HLA-G.

In some embodiments, a method of disrupting, inhibiting, or blocking MHCI-induced ILT2 and/or ILT4 activity in a subject, comprisesadministering to the subject an effective amount of an ILT2-bindingagent, an ILT4-binding agent, or an ILT2/ILT4-binding agent. In someembodiments, a method of disrupting, inhibiting, or blocking MHCI-induced ILT2 activity in a subject, comprises administering to thesubject an effective amount of an ILT2-binding agent or anILT2/ILT4-binding agent described herein. In some embodiments, a methodof disrupting, inhibiting, or blocking MHC I-induced ILT4 activity in asubject, comprises administering to the subject an effective amount ofan ILT4-binding agent or an ILT2/ILT4-binding agent described herein. Insome embodiments, a method of disrupting, inhibiting, or blocking MHCI-induced ILT2 and/or ILT4 activity in a subject, comprisesadministering to the subject an effective amount of an ILT2/ILT4-bindingagent described herein. In some embodiments of the methods describedherein, the MHC I molecule is HLA-A, HLA-B, HLA-C, HLA-E, and/or HLA-G.

In some embodiments, a method of disrupting, inhibiting, or blockingILT2-induced suppression of myeloid cells in a subject, comprisesadministering to the subject an effective amount of an ILT2-bindingagent or an ILT2/ILT4-binding agent described herein. In someembodiments, a method of disrupting, inhibiting, or blockingILT4-induced suppression of myeloid cell activity in a subject,comprises administering to the subject an effective amount of anILT4-binding agent or an ILT2/ILT4-binding agent described herein.

In some embodiments, a method of inhibiting or decreasing MDSC activityin a subject comprises administering to the subject an effective amountof an ILT4-binding agent, or an ILT2/ILT4-binding agent describedherein.

In some embodiments, a method of enhancing or increasing NK cellactivity in a subject comprises administering to the subject aneffective amount of an ILT2-binding agent, or an ILT2/ILT4-binding agentdescribed herein. In some embodiments, a method of enhancing orincreasing NK cell activity in a subject comprises administering to thesubject an effective amount of an ILT2/ILT4-binding agent describedherein.

In some embodiments, a method of enhancing or increasing CTL activity ina subject comprises administering to the subject an effective amount ofan ILT2-binding agent, or an ILT2/ILT4-binding agent described herein.In some embodiments, a method of enhancing or increasing CTL activity ina subject comprises administering to the subject an ILT2/ILT4-bindingagent described herein.

In some embodiments, a method of enhancing or increasing macrophagephagocytosis in a subject comprises administering to the subject aneffective amount of an ILT2-binding agent, or an ILT2/ILT4-binding agentdescribed herein. In some embodiments, a method of enhancing orincreasing macrophage phagocytosis in a subject comprises administeringto the subject an ILT2/ILT4-binding agent described herein.

In some embodiments, a method of treating cancer in a subject comprisesadministering to the subject a therapeutically effective amount of anILT2-binding agent, an ILT4-binding agent, or an ILT2/ILT4-binding agentdescribed herein. In some embodiments, the cancer is mesothelioma,glioblastoma, renal cell carcinoma (including cancer arising from theclear cell type and papillary cell type), non-small cell lung cancer,melanoma, pancreatic ductal adenocarcinoma, gastric cancer, squamouscell carcinoma of the head and neck, biliary duct cancer, breast cancer,ovarian cancer, cervical cancer, endocervical cancer, colorectal cancer,or esophageal cancer. In some embodiments, the cancer is an advancedsolid tumor.

In some embodiments, the cancer is pancreatic cancer, lung cancer, headand neck cancer, prostate cancer, skin cancer, stomach cancer,intestinal cancer, ovarian cancer, cervical cancer, uterine cancer,endometrial cancer, urinary bladder cancer, brain cancer, liver cancer,kidney cancer, or testicular cancer. In some embodiments, the cancer isa hematologic cancer. In some embodiments, the cancer is a myelogenousleukemia. In some embodiments, the myelogenous cancer is acute myeloidleukemia (AML). In some embodiments, the myelogenous cancer is a chronicmyeloid leukemia. In some embodiments, the cancer is a myelodysplasticsyndrome. Myelodysplastic syndromes (MDS) are a group of cancers inwhich immature blood cells in the bone marrow do not mature andtherefore do not become healthy blood cells. In some embodiments,myelodysplastic syndrome develops into AML.

In some embodiments, a method of inhibiting tumor growth in a subjectcomprises administering to the subject a therapeutically effectiveamount of an ILT2-binding agent, an ILT4-binding agent, or anILT2/ILT4-binding agent described herein. In some embodiments, a methodof increasing or enhancing an immune response to a tumor or tumor cellsin a subject comprises administering to the subject a therapeuticallyeffective amount of an ILT2-binding agent, an ILT4-binding agent, or anILT2/ILT4-binding agent described herein. In some embodiments, a methodof activating or enhancing a persistent or long-term immune response toa tumor or tumor cells in a subject comprises administering to thesubject a therapeutically effective amount of an ILT2-binding agent, anILT4-binding agent, or an ILT2/ILT4-binding agent described herein. Insome embodiments, a method of inhibiting tumor relapse or tumor regrowthin a subject comprises administering to the subject a therapeuticallyeffective amount of an ILT2-binding agent, an ILT4-binding agent, or anILT2/ILT4-binding agent described herein. In some embodiments a methodof inducing a persistent or long-term immunity that inhibits tumorrelapse or tumor regrowth in a subject comprises administering to thesubject a therapeutically effective amount of an ILT2-binding agent, anILT4-binding agent, or an ILT2/ILT4-binding agent described herein. Insome embodiments, the tumor is a a pancreatic tumor, a breast tumor, alung tumor, a non-small cell lung tumor, a head and neck tumor, acolorectal tumor, a prostate tumor, a skin tumor, a melanoma, a gastrictumor, a colorectal tumor, an ovarian tumor, a cervical tumor, a uterinetumor, an endometrial tumor, an endocervical tumor, a bladder tumor, abrain tumor, an esophageal tumor, a liver tumor, a kidney tumor, a renaltumor, mesothelioma, glioblastoma, a biliary duct tumor, or a testiculartumor.

In some embodiments, a method of activating myeloid cells in the tumormicroenvironment in a subject with a tumor comprises administering tothe subject a therapeutically effective amount of an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4-binding agent described herein.In some embodiments, the myeloid cells are primary dendritic cells ortolerogenic dendritic cells. In some embodiments, the myeloid cells aremonocytes or macrophages.

In some embodiments, a method of reactivating tolerogenic dendriticcells in a subject comprises administering to the subject atherapeutically effective amount of an ILT2-binding agent, anILT4-binding agent, or an ILT2/ILT4-binding agent described herein. Insome embodiments, the tolerogenic dendritic cells are found in the tumormicroenvironment.

In some embodiments of all the methods described herein, the ILT-bindingagent is administered to a subject as part of a combination therapy. Insome embodiments, the combination therapy comprises at least oneadditional therapeutic agent. In some embodiments, the combinationtherapy comprises an immune checkpoint inhibitor, such as an anti-PD-1antibody or an anti-PD-L1 antibody. In some embodiments, the anti-PD-1antibody is Pembrolizumab (MK-3475; KEYTRUDA), Pidilizumab (CT-011),Nivolumab (OPDIVO), Durvalumab (MEDI0680), Cemiplimab (REGN2810),Tislelizumab (BGB-A317), Spartalizumab (PDR-001), or STI-A1110.

Also disclosed is the use of an ILT-binding agent described herein inthe manufacture of a medicament for the treatment of cancer. In someembodiments, an ILT-binding agent described herein is for use in thetreatment of cancer. In some embodiments, an ILT-binding agent describedherein is for use in inhibition of tumor growth.

In some embodiments of all the aforementioned methods, the subject ishuman.

Where aspects or embodiments of the disclosure are described in terms ofa Markush group or other grouping of alternatives, the presentdisclosure encompasses not only the entire group listed as a whole, butalso each member of the group individually and all possible subgroups ofthe main group, and also the main group absent one or more of the groupmembers. The present disclosure also envisages the explicit exclusion ofone or more of any of the group members in the claimed disclosure.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1. Expression of ILT2 and ILT4 in various immune cells assayed byflow cytometry.

FIG. 2. Inhibition of the interaction between ILT2 or ILT4 and MHC Imolecules by anti-ILT antibodies.

FIG. 3. Binding of anti-ILT2/ILT4 antibodies to monocytes.

FIG. 4A and 4B. Inhibition of the interaction between human ILT2 or ILT4and MHC I molecules by anti-ILT antibodies.

FIG. 5. Inhibition of the interaction between cyno ILT2 and MHC Imolecules by anti-ILT antibodies.

FIG. 6. Effect of anti-ILT antibodies on cytolytic activity of NKLcells.

FIG. 7. Effect of anti-ILT antibodies on activity of human primary NKcells.

FIG. 8. Effect of anti-ILT antibodies on cytolytic activity of primaryNK cells.

FIG. 9. Effect of anti-ILT antibodies on cytolytic activity of primaryNK cells in ADCC assay with classic MHC-I-expressing target cells.

FIG. 10. Effect of anti-ILT antibodies on MDSC activity in MLR assay.

FIG. 11A-11C. Effect of anti-ILT antibodies on MDSC activity in MLRassay.

FIG. 12. Effect of anti-ILT antibodies on LPS-mediated stimulation ofhuman PBMCs as assessed by cytokine production.

FIG. 13. Effect of anti-ILT antibodies on LPS-mediated stimulation ofcyno PBMCs as assessed by cytokine production.

FIG. 14. Effect of anti-ILT antibodies on LPS-mediated stimulation oftolerized dendritic cells as assessed by cytokine production.

FIG. 15. Effect of anti-ILT antibodies on cytokine production fromHMGB1-treated cells.

FIG. 16. Effect of anti-ILT antibodies on cytokine production from STINGagonist-treated cells.

FIG. 17. Effect of anti-ILT antibodies suppression of T-cell mediatedstimulation of myeloid cells.

FIG. 18. Effect of anti-ILT antibodies on macrophage phagocytosis.

FIG. 19. Effect of anti-ILT antibodies on cytokine production bydendritic cells.

FIG. 20. Effect of anti-ILT antibodies on cytokine production from humanblood cells.

FIG. 21. Effect of anti-ILT antibodies on cytokine production from cynoblood cells.

FIG. 22. Effect of anti-ILT antibodies on cytolytic activity of T cells.

FIGS. 23A-23C. Synergetic effects of an anti-ILT2/ILT4 antibody andanti-PD-1 antibody on T cell activation and cytokine release from Tcells.

FIG. 24. Effects of anti-ILT2/ILT4 antibodies on polarization ofmonocyte-derived macrophages by assaying expression markers via flowcyometry.

DETAILED DESCRIPTION

The present disclosure provides novel agents, including but not limitedto polypeptides such as antibodies, that bind immunoglobulin-liketranscript 2 (ILT2), immunoglobulin-like transcript 4 (ILT4), or bothILT2 and ILT4. As used herein the term “ILT-binding agents” refers toILT2-binding agents, ILT4-binding agents, and ILT2/ILT4-binding agents.As used herein “ILT2/ILT4-binding agents” refers to agents that bindboth ILT2 and ILT4, and may also be referred to as ILT2/ILT4 dualbinders. The ILT-binding agents include, but are not limited to,polypeptides, antibodies (including antigen-binding fragments thereof),scaffold proteins, and heterodimeric molecules. ILT-binding agentsinclude, but are not limited to, antagonists of ILT2 and/or ILT4activity, inhibitors of ILT2 and/or ILT4 activity, and/or agents thatinhibit ILT2 and/or ILT4 suppressive activity. Related polypeptides,polynucleotides, vectors, compositions comprising the agents, cellscomprising the related polynucleotides or vectors, and methods of makingthe agents are also provided. Methods of using the novel ILT-bindingagents are also provided.

I. Definitions

Unless otherwise defined herein, technical and scientific terms used inthe present description have the meanings that are commonly understoodby those of ordinary skill in the art. Whenever appropriate, terms usedin the singular will also include the plural and vice versa. In theevent that any description of a term set forth conflicts with anydocument incorporated herein by reference, the description of the termset forth below shall control.

The term “binding agent” as used herein refers to a molecule that bindsa specific antigen or target (e.g., ILT2 and/or ILT4). A binding agentmay comprise a protein, peptide, nucleic acid, carbohydrate, lipid, orsmall molecular weight compound. In some embodiments, a binding agentcomprises a full-length antibody. In some embodiments, a binding agentis an antigen-binding fragment of an antibody. In some embodiments, abinding agent comprises an alternative protein scaffold or artificialscaffold (e.g., a non-immunoglobulin backbone). In some embodiments, abinding agent is a fusion protein comprising an antigen-binding site. Insome embodiments, a binding agent is a bispecific or multispecificmolecule comprising at least one antigen-binding site.

The term “antibody” is used herein in the broadest sense and encompassesvarious antibody structures, including but not limited to, animmunoglobulin molecule that recognizes and binds a target through atleast one antigen-binding site, polyclonal antibodies, recombinantantibodies, monoclonal antibodies, chimeric antibodies, humanizedantibodies, human antibodies, bispecific antibodies, multispecificantibodies, diabodies, tribodies, tetrabodies, single chain Fv (scFv)antibodies, and antibody fragments as long as they exhibit the desiredantigen-binding activity.

The term “intact antibody” or “full-length antibody” refers to anantibody having a structure substantially similar to a native antibodystructure. This includes, for example, an antibody comprising two lightchains each comprising a variable region and a light chain constantregion (CL) and two heavy chains each comprising a variable region andat least heavy chain constant regions CH1, CH2, and CH3. Generally, anintact antibody includes a hinge region (or a portion thereof) betweenthe CH1 and CH2 regions.

The term “antibody fragment” or “antibody fragments” as used hereinrefers to a molecule other than an intact antibody that comprises aportion of an antibody and generally an antigen-binding site. Examplesof antibody fragments include, but are not limited to, Fab, Fab′,F(ab′)2, Fv, single chain antibody molecules (e.g., scFv), sc(Fv)₂,disulfide-linked scFv (dsscFv), diabodies, tribodies, tetrabodies,minibodies, dual variable domain antibodies (DVD), single variabledomain antibodies (e.g., camelid antibodies), and multispecificantibodies formed from antibody fragments.

The term “monoclonal antibody” as used herein refers to a substantiallyhomogenous antibody population involved in the highly specificrecognition and binding of a single antigenic determinant or epitope.The term “monoclonal antibody” encompasses intact and full-lengthmonoclonal antibodies as well as antibody fragments (e.g., Fab, Fab′,F(ab′)₂, Fv), single chain antibodies (e.g., scFv), fusion proteinscomprising an antibody fragment, and any other modified immunoglobulinmolecule comprising at least one antigen-binding site. Furthermore,“monoclonal antibody” refers to such antibodies made by any number oftechniques, including but not limited to, hybridoma production, phagelibrary display, recombinant expression, and transgenic animals.

The term “chimeric antibody” refers to an antibody in which a portion ofthe heavy and/or light chain is derived from a first source or species,while the remainder of the heavy and/or light chain is derived from adifferent source or species.

The term “humanized antibody” as used herein refers to an antibody thatcomprises a human heavy chain variable region and a light chain variableregion wherein the native CDR amino acid residues are replaced byresidues from corresponding CDRs from a nonhuman antibody (e.g., mouse,rat, rabbit, or nonhuman primate), wherein the nonhuman antibody has thedesired specificity, affinity, and/or activity. In some embodiments, oneor more framework region amino acid residues of the human heavy chain orlight chain variable regions are replaced by corresponding residues fromthe nonhuman antibody. Furthermore, humanized antibodies can compriseamino acid residues that are not found in the human antibody or in thenonhuman antibody. In some embodiments, these modifications are made tofurther refine and/or optimize antibody characteristics. In someembodiments, the humanized antibody comprises at least a portion of ahuman immunoglobulin constant region (e.g., CH1, CH2, CH3, Fc, and/orhinge region).

The term “human antibody” as used herein refers to an antibody thatpossesses an amino acid sequence that corresponds to an antibodyproduced by a human and/or an antibody that has been made using any ofthe techniques that are known to those of skill in the art for makinghuman antibodies. These techniques include, but not limited to, phagedisplay libraries, yeast display libraries, transgenic animals,recombinant protein production, and B-cell hybridoma technology.

The terms “epitope” and “antigenic determinant” are used interchangeablyherein and refer to that portion of an antigen or target capable ofbeing recognized and bound by a particular antibody. When the antigen ortarget is a polypeptide, epitopes can be formed both from contiguousamino acids and noncontiguous amino acids juxtaposed by tertiary foldingof the protein. Epitopes formed from contiguous amino acids (alsoreferred to as linear epitopes) are typically retained upon proteindenaturing, whereas epitopes formed by tertiary folding (also referredto as conformational epitopes) are typically lost upon proteindenaturing. An epitope typically includes at least 3, and more usually,at least 5, 6, 7, or 8-10 amino acids in a unique spatial conformation.Epitopes can be predicted using any one of a large number of softwarebioinformatic tools available on the internet. X-ray crystallography maybe used to characterize an epitope on a target protein by analyzing theamino acid residue interactions of an antigen/antibody complex.

The term “specifically binds” as used herein refers to an agent thatinteracts more frequently, more rapidly, with greater duration, withgreater affinity, or with some combination of the above to a particularantigen, epitope, protein, or target molecule than with alternativesubstances. A binding agent that specifically binds an antigen can beidentified, for example, by immunoassays, ELISAs, surface plasmonresonance (SPR), or other techniques known to those of skill in the art.In some embodiments, an agent that specifically binds an antigen (e.g.,human ILT2) can bind related antigens (e.g., rhesus ILT2 and/or cynoILT2). In some embodiments, an agent that specifically binds an antigen(e.g., human ILT2) can bind a second antigen (e.g., human ILT4) and isreferred to herein as a “dual binder”. In some embodiments, a bindingagent that specifically binds an antigen can bind the target antigen ata higher affinity than its affinity for a different antigen. Thedifferent antigen can be a related antigen. In some embodiments, abinding agent that specifically binds an antigen can bind the targetantigen with an affinity that is at least 20 times greater, at least 30times greater, at least 40 times greater, at least 50 times greater, atleast 60 times greater, at least 70 times greater, at least 80 timesgreater, at least 90 times greater, or at least 100 times greater, thanits affinity for a different antigen. In some embodiments, a bindingagent that specifically binds a particular antigen binds a differentantigen at such a low affinity that binding cannot be detected using anassay described herein or otherwise known in the art. In someembodiments, affinity is measured using SPR technology in a Biacoresystem as described herein or as known to those of skill in the art.

The terms “polypeptide” and “peptide” and “protein” are usedinterchangeably herein and refer to polymers of amino acids of anylength. The polymer may be linear or branched, it may comprise modifiedamino acids, and it may be interrupted by non-amino acids. The termsalso encompass an amino acid polymer that has been modified naturally orby intervention; for example, disulfide bond formation, glycosylation,lipidation, acetylation, phosphorylation, or any other manipulation ormodification. Also included within the definition are, for example,polypeptides containing one or more analogs of an amino acid, includingbut not limited to, unnatural amino acids, as well as othermodifications known in the art. It is understood that, because thepolypeptides of this disclosure may be based upon antibodies, the term“polypeptide” encompasses polypeptides as a single chain andpolypeptides of two or more associated chains.

The terms “polynucleotide” and “nucleic acid” and “nucleic acidmolecule” are used interchangeably herein and refer to polymers ofnucleotides of any length, and include DNA and RNA. The nucleotides canbe deoxyribonucleotides, ribonucleotides, modified nucleotides or bases,and/or their analogs, or any substrate that can be incorporated into apolymer by DNA or RNA polymerase.

The terms “identical” or percent “identity” in the context of two ormore nucleic acids or polypeptides, refer to two or more sequences orsubsequences that are the same or have a specified percentage ofnucleotides or amino acid residues that are the same, when compared andaligned (introducing gaps, if necessary) for maximum correspondence, notconsidering any conservative amino acid substitutions as part of thesequence identity. The percent identity may be measured using sequencecomparison software or algorithms or by visual inspection. Variousalgorithms and software that may be used to obtain alignments of aminoacid or nucleotide sequences are well-known in the art. These include,but are not limited to, BLAST, ALIGN, Megalign, BestFit, GCG WisconsinPackage, and variants thereof. In some embodiments, two nucleic acids orpolypeptides of the disclosure are substantially identical, meaning theyhave at least 70%, at least 75%, at least 80%, at least 85%, at least90%, and in some embodiments at least 95%, 96%, 97%, 98%, 99% nucleotideor amino acid residue identity, when compared and aligned for maximumcorrespondence, as measured using a sequence comparison algorithm or byvisual inspection. In some embodiments, identity exists over a region ofthe sequences that is at least about 10, at least about 20, at leastabout 20-40, at least about 40-60, at least about 60-80 nucleotides oramino acid residues in length, or any integral value there between. Insome embodiments, identity exists over a longer region than 60-80nucleotides or amino acid residues, such as at least about 80-100nucleotides or amino acid residues, and in some embodiments thesequences are substantially identical over the full length of thesequences being compared, for example, (i) the coding region of anucleotide sequence or (ii) an amino acid sequence.

The phrase “conservative amino acid substitution” as used herein refersto a substitution in which one amino acid residue is replaced withanother amino acid residue having a similar side chain. Families ofamino acid residues having similar side chains have been generallydefined in the art, including basic side chains (e.g., lysine, arginine,histidine), acidic side chains (e.g., aspartic acid, glutamic acid),uncharged polar side chains (e.g., glycine, asparagine, glutamine,serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g.,alanine, valine, leucine, isoleucine, proline, phenylalanine,methionine, tryptophan), beta-branched side chains (e.g., threonine,valine, isoleucine) and aromatic side chains (e.g., tyrosine,phenylalanine, tryptophan, histidine). For example, substitution of analanine for a valine is considered to be a conservative substitution.Generally, conservative substitutions in the sequences of polypeptidesand/or antibodies do not abrogate the binding of the polypeptide orantibody to the target binding site. Methods of identifying nucleotideand amino acid conservative substitutions that do not eliminate bindingare well-known in the art.

The term “vector” as used herein means a construct that is capable ofdelivering, and usually expressing, one or more gene(s) or sequence(s)of interest in a host cell. Examples of vectors include, but are notlimited to, viral vectors, naked DNA or RNA expression vectors, plasmid,cosmid, or phage vectors, DNA or RNA expression vectors associated withcationic condensing agents, and DNA or RNA expression vectorsencapsulated in liposomes.

The term “isolated” as used herein refers to a polypeptide, solubleprotein, antibody, polynucleotide, vector, cell, or composition that isin a form not found in nature. An “isolated” antibody is substantiallyfree of material from the cellular source from which it is derived. Insome embodiments, isolated polypeptides, soluble proteins, antibodies,polynucleotides, vectors, cells, or compositions are those that havebeen purified to a degree that they are no longer in a form in whichthey are found in nature. In some embodiments, a polypeptide, solubleprotein, antibody, polynucleotide, vector, cell, or composition that isisolated is substantially pure. A polypeptide, soluble protein,antibody, polynucleotide, vector, cell, or composition can be isolatedfrom a natural source (e.g., tissue) or from a source such as anengineered cell line.

The term “substantially pure” as used herein refers to material that isat least 50% pure (i.e., free from contaminants), at least 90% pure, atleast 95% pure, at least 98% pure, or at least 99% pure.

The term “subject” refers to any animal (e.g., a mammal), including, butnot limited to, humans, non-human primates, canines, felines, rabbits,rodents, and the like.

The term “pharmaceutically acceptable” as used herein refers to asubstance approved or approvable by a regulatory agency or listed in theU.S. Pharmacopeia, European Pharmacopeia, or other generally recognizedpharmacopeia for use in animals, including humans.

The terms “pharmaceutically acceptable excipient, carrier, or adjuvant”or “acceptable pharmaceutical carrier” as used herein refer to anexcipient, carrier, or adjuvant that can be administered to a subject,together with at least one therapeutic agent, and that is generallysafe, non-toxic, and has no effect on the pharmacological activity ofthe therapeutic agent. In general, those of skill in the art andgovernment agencies consider a pharmaceutically acceptable excipient,carrier, or adjuvant to be an inactive ingredient of any formulation.

The term “pharmaceutical formulation” or “pharmaceutical composition” asused herein refers to a preparation that is in such form as to permitthe biological activity of the agent to be effective. A pharmaceuticalformulation or composition generally comprises additional components,such as a pharmaceutically acceptable excipient, carrier, adjuvant,buffers, etc.

The term “effective amount” or “therapeutically effective amount” asused herein refers to the amount of an agent that is sufficient toreduce and/or ameliorate the severity and/or duration of (i) a disease,disorder or condition in a subject, and/or (ii) a symptom in a subject.The term also encompasses an amount of an agent necessary for the (i)reduction or amelioration of the advancement or progression of a givendisease, disorder, or condition, (ii) reduction or amelioration of therecurrence, development, or onset of a given disease, disorder, orcondition, and/or (iii) the improvement or enhancement of theprophylactic or therapeutic effect(s) of another agent or therapy (e.g.,an agent other than the binding agents provided herein).

The term “therapeutic effect” as used herein refers to the effect and/orability of an agent to reduce and/or ameliorate the severity and/orduration of (i) a disease, disorder, or condition in a subject, and/or(ii) a symptom in a subject. The term also encompasses the ability of anagent to (i) reduce or ameliorate the advancement or progression of agiven disease, disorder, or condition, (ii) reduce or ameliorate therecurrence, development, or onset of a given disease, disorder, orcondition, and/or (iii) to improve or enhance the prophylactic ortherapeutic effect(s) of another agent or therapy (e.g., an agent otherthan the binding agents provided herein).

The term “treat” or “treatment” or “treating” or “to treat” or“alleviate” or alleviation” or “alleviating” or “to alleviate” as usedherein refers to therapeutic measures that aim to slow down, lessensymptoms of, and/or halt progression of a pathologic condition ordisorder. Thus, those in need of treatment include those already withthe disorder.

The term “prevent” or “prevention” or “preventing” as used herein refersto the partial or total inhibition of the development, recurrence,onset, or spread of a disease, disorder, or condition, or a symptomthereof in a subject.

The term “immune response” as used herein includes responses from boththe innate immune system and the adaptive immune system. It includesboth cell-mediated and/or humoral immune responses. It includes bothT-cell and B-cell responses, as well as responses from other cells ofthe immune system such as natural killer (NK) cells, monocytes,macrophages, dendritic cells, etc.

As used herein, reference to “about” or “approximately” a value orparameter includes (and describes) embodiments that are directed to thatvalue or parameter. For example, a description referring to “about X”includes description of “X”.

As used in the present disclosure and claims, the singular forms “a”,“an” and “the” include plural forms unless the context clearly dictatesotherwise.

It is understood that wherever embodiments are described herein with theterm “comprising” otherwise analogous embodiments described in terms of“consisting of” and/or “consisting essentially of” are also provided. Itis also understood that wherever embodiments are described herein withthe phrase “consisting essentially of” otherwise analogous embodimentsdescribed in terms of “consisting of” are also provided.

The term “and/or” as used in a phrase such as “A and/or B” herein isintended to include both A and B; A or B; A (alone); and B (alone).Likewise, the term “and/or” as used in a phrase such as “A, B, and/or C”is intended to encompass each of the following embodiments: A, B, and C;A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A(alone); B (alone); and C (alone).

IL ILT-Binding Agents

Amino acid (aa) sequences for human ILT2 (UniProtKB No. Q8NHL6), humanILT4 (UniProtKB No. Q8N423), rhesus macaque (“rhesus”) ILT2 (NCBI RefNo. XP_028694980.1), and cynomolgus monkey (“cyno”) ILT2 (in housesequence has 98% identity to UniProtKB No. A0A2K5VN04) are providedherein as SEQ ID NO:1, SEQ ID NO:8, SEQ ID NO:15, and SEQ ID NO:166,respectively. As used herein, reference to amino acid positions of ILT2or ILT4 refer to the numbering of amino acid sequences including thesignal sequence.

A genomic orthologue for human ILT2 is found in the monkey genome,however, no genomic orthologue for human ILT4 appears to exist.Expression patterns of the monkey ILT2 orthologue are comparable to thecombined expression patterns of human ILT2 and human ILT4. Without beingbound by theory, it is believed that the ILT2 orthologue in monkeys mayhave biological/functional capabilities that are equivalent to acombination of the biological functions of human ILT2 and human ILT4.

ILT2 is a single pass type I transmembrane protein with a predictedmolecular weight of approximately 71 kDa. ILT2 (human, rhesus, and cyno)is characterized by an extracellular domain comprising four Ig-like C2type domains, a transmembrane domain, and a long cytoplasmic domaincontaining 4 ITIM domains (see, e.g., Borges et al., 1997, J. Immunol.,159:5192-5196). The four Ig-like C2-type domains may be referred toherein as Domain 1 (D1), Domain 2 (D2), Domain 3 (D3), and Domain 4(D4). D1 is situated at the N-terminal portion of the protein, then D2,D3, with D4 situated closest to the transmembrane region. Ascharacterized within UniProtKB, human ILT2 is a protein of 650 aminoacids (aa)—the signal sequence is aa 1-23, the extracellular domain isaa 24-461, the transmembrane region is aa 462-482, and the cytoplasmicdomain is aa 483-650. Within the extracellular domain, D1 is aa 27-115,D2 is aa 116-221, D3 is aa 222-312, D4 is aa 313-409, and the “stemregion” is aa 410-461. Within the cytoplasmic domain, ITIMs are aa531-536, 560-565, 612-617, and 642-647. Rhesus ILT2 is a protein of 639amino acids (aa)—as compared to structural characterization of humanILT2 the signal sequence is aa 1-23, the extracellular domain is aa24-460, the transmembrane region is aa 461-481, and the cytoplasmicdomain is aa 482-639. Within the extracellular domain, D1 is aa 27-114,D2 is aa 115-220, D3 is aa 221-311, D4 is aa 312-408, and the “stemregion” is aa 409-460. Within the cytoplasmic domain, ITIMs are aa530-535, 559-564, 601-606, and 631-636. Cyno ILT2 is a protein of 651amino acids (aa)—as compared to structural characterization of humanILT2 the signal sequence is aa 1-23, the extracellular domain is aa24-461, the transmembrane region is aa 462-482, and the cytoplasmicdomain is aa 483-651. Within the extracellular domain, D1 is aa 27-114,D2 is aa 115-220, D3 is aa 221-311, D4 is aa 312-408, and the “stemregion” is aa 409-461. Within the cytoplasmic domain, ITIMs are aa531-536, 561-566, 613-618, and 643-648. ILT2 is expressed (to varyingdegrees) on natural killer (NK) cells, monocytes, macrophages,eosinophils, basophils, dendritic cells (DCs), subset of T-cells, andB-cells. Various ligands are known to interact with ILT2, including HLAclass I molecules (e.g., HLA-A, HLA-B, HLA-C, HLA-E, HLA-F, and HLA-G).ILT2 appears to bind more strongly with the “non-classical” MHC Imolecule HLA-G than to classical HLA class I molecules.

ILT4 has a structure very similar to ILT2. It is a single pass type Itransmembrane protein with a predicted molecular weight of approximately65 kDa. ILT4 is characterized by an extracellular domain comprising fourIg-like C2 type domains, a transmembrane domain, and a long cytoplasmicdomain containing 3 ITIM domains (see, e.g., Borges et al., 1997, J.Immunol., 159:5192-5196). As described for ILT2, the four Ig-likeC2-type domains may be referred to herein as D1, D2, D3, and D4. D1 issituated at the N-terminal portion of the protein, then D2, D3, with D4situated closest to the transmembrane region. As characterized withinUniProtKB, human ILT4 is a protein of 598 amino acids (aa)—the signalsequence is aa 1-21, the extracellular domain is aa 22-461, thetransmembrane region is aa 462-482, and the cytoplasmic domain is aa483-598. Within the extracellular domain, D1 is aa 27-110, D2 is aa111-229, D3 is aa 230-318, D4 is aa 330-419, and the “stem region” is aa420-461. Within the cytoplasmic domain, ITIMs are aa 531-536, 560-565,and 590-595. ILT4 is expressed on myeloid cells such as monocytes,macrophages, dendritic cells, but not on lymphoid cells. ILT4 has beenobserved to bind a variety of ligands, notably HLA class I molecules,ANGPTL proteins, myelin inhibitors, and β-amyloid.

It is understood that the domains of ILT2 or ILT4 (e.g., human ILT2,rhesus ILT2, cyno ILT2, or human ILT4) may be defined differently bythose of skill in the art, therefore the N-terminal amino acids and theC-terminal amino acids of any ILT2 or ILT4 domain or region may vary by1, 2, 3, 4, 5, or more amino acid residues.

The present disclosure provides agents that bind ILT2, ILT4, or ILT2 andILT4, i.e., ILT-binding agents. The agents that bind both ILT2 and ILT4(ILT2/ILT4-binding agents) may be referred to herein as “dual binders”.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds ILT2 or a fragment of ILT2. In some embodiments, a fragment ofILT2 comprises the extracellular domain of ILT2. In some embodiments, afragment of ILT2 comprises one or more of the Ig-like C2 type domains(e.g., D1, D2, D3, and/or D4). In some embodiments, a fragment of ILT2comprises D1 and D2. In some embodiments, a fragment of ILT2 comprisesD2 and D3. In some embodiments, a fragment of ILT2 comprises D3 and D4.In some embodiments, a fragment of ILT2 comprises D1, D2, and D3. Insome embodiments, a fragment of ILT2 comprises D2, D3, and D4. In someembodiments, a fragment of ILT2 comprises one or more of the Ig-like C2type domains and the stem region. In some embodiments, a fragment ofILT2 comprises D4-stem, D3-D4-stem, or D2-D3-D4-stem.

In some embodiments, the extracellular domain of human ILT2 comprisesamino acids 24-461 of SEQ ID NO:1. In some embodiments, D1 of human ILT2comprises amino acids 27-115 of SEQ ID NO:1. In some embodiments, D2 ofhuman ILT2 comprises amino acids 116-221 of SEQ ID NO:1. In someembodiments, D3 of human ILT2 comprises amino acids 222-312 of SEQ IDNO:1. In some embodiments, D4 of human ILT2 comprises amino acids313-409 of SEQ ID NO:1. In some embodiments, D1-D2 of human ILT2comprises amino acids 27-221 of SEQ ID NO:1. In some embodiments, D2-D3of human ILT2 comprises amino acids 116-312 of SEQ ID NO:1. In someembodiments, D3-D4 of human ILT2 comprises amino acids 222-409 of SEQ IDNO:1. In some embodiments, D1-D2-D3 of human ILT2 comprises amino acids27-312 of SEQ ID NO:1. In some embodiments, D2-D3-D4 of human ILT2comprises amino acids 116-409 of SEQ ID NO:1. In some embodiments,D4-stem of human ILT2 comprises amino acids 313-461 of SEQ ID NO:1. Insome embodiments, D3-D4-stem of human ILT2 comprises amino acids 222-461of SEQ ID NO:1. In some embodiments, D2-D3-D4-stem of human ILT2comprises amino acids 116-461 of SEQ ID NO:1. In some embodiments, afragment of human ILT2 comprises the amino acid sequence of SEQ ID NO:3.In some embodiments, a fragment of human ILT2 comprises the amino acidsequence of SEQ ID NO:4. In some embodiments, a fragment of human ILT2comprises the amino acid sequence of SEQ ID NO:5. In some embodiments, afragment of human ILT2 comprises the amino acid sequence of SEQ ID NO:6.In some embodiments, a fragment of human ILT2 comprises the amino acidsequence of SEQ ID NO:7. In some embodiments, a fragment of human ILT2comprises the amino acid sequence of SEQ ID NO:4 and SEQ ID NO:5. Insome embodiments, a fragment of human ILT2 comprises the amino acidsequence of SEQ ID NO:5 and SEQ ID NO:6. In some embodiments, a fragmentof human ILT2 comprises the amino acid sequence of SEQ ID NO:6 and SEQID NO:7. In some embodiments, a fragment of human ILT2 comprises theamino acid sequence of SEQ ID NO:4, SEQ ID NO:5, and SEQ ID NO:6. Insome embodiments, a fragment of human ILT2 comprises the amino acidsequence of SEQ ID NO:5, SEQ ID NO:6, and SEQ ID NO:7.

In some embodiments, the extracellular domain of rhesus ILT2 comprisesamino acids 24-460 of SEQ ID NO:15. In some embodiments, D1 of rhesusILT2 comprises amino acids 27-114 of SEQ ID NO:15. In some embodiments,D2 of rhesus ILT2 comprises amino acids 115-220 of SEQ ID NO:15. In someembodiments, D3 of rhesus ILT2 comprises amino acids 221-311 of SEQ IDNO:15. In some embodiments, D4 of rhesus ILT2 comprises amino acids312-408 of SEQ ID NO:15. In some embodiments, D1-D2 of rhesus ILT2comprises amino acids 27-220 of SEQ ID NO:15. In some embodiments, D2-D3of rhesus ILT2 comprises amino acids 115-311 of SEQ ID NO:15. In someembodiments, D3-D4 of rhesus ILT2 comprises amino acids 221-408 of SEQID NO:15. In some embodiments, D1-D2-D3 of rhesus ILT2 comprises aminoacids 27-311 of SEQ ID NO:15. In some embodiments, D2-D3-D4 of rhesusILT2 comprises amino acids 115-408 of SEQ ID NO:15. In some embodiments,D4-stem of rhesus ILT2 comprises amino acids 312-460 of SEQ ID NO:15. Insome embodiments, D3-D4-stem of rhesus ILT2 comprises amino acids221-460 of SEQ ID NO:15. In some embodiments, D2-D3-D4-stem of rhesusILT2 comprises amino acids 115-460 of SEQ ID NO:15. In some embodiments,a fragment of rhesus ILT2 comprises the amino acid sequence of SEQ IDNO:17. In some embodiments, a fragment of rhesus ILT2 comprises theamino acid sequence of SEQ ID NO:18. In some embodiments, a fragment ofrhesus ILT2 comprises the amino acid sequence of SEQ ID NO:19. In someembodiments, a fragment of rhesus ILT2 comprises the amino acid sequenceof SEQ ID NO:20. In some embodiments, a fragment of rhesus ILT2comprises the amino acid sequence of SEQ ID NO:21. In some embodiments,a fragment of rhesus ILT2 comprises the amino acid sequence of SEQ IDNO:18 and SEQ ID NO:19. In some embodiments, a fragment of human ILT2comprises the amino acid sequence of SEQ ID NO:19 and SEQ ID NO:20. Insome embodiments, a fragment of human ILT2 comprises the amino acidsequence of SEQ ID NO:20 and SEQ ID NO:21. In some embodiments, afragment of human ILT2 comprises the amino acid sequence of SEQ IDNO:18, SEQ ID NO:19, and SEQ ID NO:20. In some embodiments, a fragmentof human ILT2 comprises the amino acid sequence of SEQ ID NO:19, SEQ IDNO:20, and SEQ ID NO:21.

In some embodiments, the extracellular domain of cyno ILT2 comprisesamino acids 24-461 of SEQ ID NO:166. In some embodiments, D1 of cynoILT2 comprises amino acids 27-114 of SEQ ID NO:166. In some embodiments,D2 of cyno ILT2 comprises amino acids 115-220 of SEQ ID NO:166. In someembodiments, D3 of cyno ILT2 comprises amino acids 221-311 of SEQ IDNO:166. In some embodiments, D4 of cyno ILT2 comprises amino acids312-408 of SEQ ID NO:166. In some embodiments, D1-D2 of cyno ILT2comprises amino acids 27-220 of SEQ ID NO:166. In some embodiments,D2-D3 of cyno ILT2 comprises amino acids 115-311 of SEQ ID NO:166. Insome embodiments, D3-D4 of cyno ILT2 comprises amino acids 221-408 ofSEQ ID NO:166. In some embodiments, D1-D2-D3 of cyno ILT2 comprisesamino acids 27-311 of SEQ ID NO:166. In some embodiments, D2-D3-D4 ofcyno ILT2 comprises amino acids 115-408 of SEQ ID NO:166. In someembodiments, D4-stem of cyno ILT2 comprises amino acids 312-461 of SEQID NO:166. In some embodiments, D3-D4-stem of cyno ILT2 comprises aminoacids 221-461 of SEQ ID NO:166. In some embodiments, D2-D3-D4-stem ofcyno ILT2 comprises amino acids 115-461 of SEQ ID NO:166. In someembodiments, a fragment of cyno ILT2 comprises the amino acid sequenceof SEQ ID NO:168. In some embodiments, a fragment of cyno ILT2 comprisesthe amino acid sequence of SEQ ID NO:169. In some embodiments, afragment of cyno ILT2 comprises the amino acid sequence of SEQ IDNO:170. In some embodiments, a fragment of cyno ILT2 comprises the aminoacid sequence of SEQ ID NO:171. In some embodiments, a fragment of cynoILT2 comprises the amino acid sequence of SEQ ID NO:172. In someembodiments, a fragment of cyno ILT2 comprises the amino acid sequenceof SEQ ID NO:169 and SEQ ID NO:170. In some embodiments, a fragment ofhuman ILT2 comprises the amino acid sequence of SEQ ID NO:170 and SEQ IDNO:171. In some embodiments, a fragment of human ILT2 comprises theamino acid sequence of SEQ ID NO:171 and SEQ ID NO:172. In someembodiments, a fragment of human ILT2 comprises the amino acid sequenceof SEQ ID NO:169, SEQ ID NO:170, and SEQ ID NO:171. In some embodiments,a fragment of human ILT2 comprises the amino acid sequence of SEQ IDNO:170, SEQ ID NO:171, and SEQ ID NO:172.

In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a fragment of ILT2 (e.g., human ILT2, rhesus ILT2, and/or cynoILT2). In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds within a specific region of ILT2. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindswithin the extracellular domain of ILT2. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds within the D1domain of ILT2. In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds within the D2 domain of ILT2. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindswithin the D3 domain of ILT2. In some embodiments, an ILT2-binding agentor an ILT2/ILT4-binding agent binds within the D4 domain of ILT2. Insome embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds within the D4-stem region of ILT2. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds within the D1-D2domains of ILT2. In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds within the D2-D3 domains of ILT2. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindswithin the D3-D4 domains of ILT2. In some embodiments, an ILT2-bindingagent or an ILT2/ILT4-binding agent binds within the D1-D2-D3 domains ofILT2. In some embodiments, an ILT2-binding agent or an ILT2/ILT4-bindingagent binds within the D2-D3-D4 domains of ILT2. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds an epitope onILT2. In some embodiments, an ILT2-binding agent or an ILT2/ILT4-bindingagent binds a conformational epitope on ILT2. In some embodiments, anILT2-binding agent does not bind other human LILRB proteins (e.g., ILT3,ILT4, ILT5, or LILRB5). In some embodiments, an ILT2/ILT4-binding agentdoes not bind other human LILRB proteins (e.g., ILT3, ILT5, or LILRB5).In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentdoes not bind one or more of the human LILRA proteins (e.g., LILRA1,LILRA2, LILRA4, LILRA5, or LILRA6). In some embodiments, an ILT2-bindingagent or an ILT2/ILT4-binding agent does not bind LILRA2, LILRA4,LILRA5, or LILRA6.

In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds human ILT2. In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds cyno ILT2 and/or rhesus ILT2. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindshuman ILT2, cyno ILT2, and rhesus ILT2. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:1. Insome embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds SEQ ID NO:2. In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:3. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds a fragmentcomprising amino acids 24-461 of SEQ ID NO:1. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds a fragmentcomprising amino acids 27-115 of SEQ ID NO:1. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds a fragmentcomprising amino acids 116-221 of SEQ ID NO:1. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds a fragmentcomprising amino acids 222-312 of SEQ ID NO:1. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds a fragmentcomprising amino acids 313-409 of SEQ ID NO:1. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds a fragmentcomprising amino acids 27-221 of SEQ ID NO:1. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds a fragmentcomprising amino acids 116-312 of SEQ ID NO:1. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds a fragmentcomprising amino acids 222-409 of SEQ ID NO:1. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:4. Insome embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds SEQ ID NO:5. In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:6. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:7.

In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds SEQ ID NO:15. In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:16. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:17. Insome embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a fragment comprising amino acids 24-460 of SEQ ID NO:15. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 27-114 of SEQ ID NO:15. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 115-220 of SEQ ID NO:15. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 221-311 of SEQ ID NO:15. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 312-408 of SEQ ID NO:15. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 27-220 of SEQ ID NO:15. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 115-311 of SEQ ID NO:15. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 221-408 of SEQ ID NO:15. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsSEQ ID NO:18. In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:19. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:20. Insome embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds SEQ ID NO:21.

In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds SEQ ID NO:166. In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:167. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:168. Insome embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a fragment comprising amino acids 24-461 of SEQ ID NO:166. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 27-114 of SEQ ID NO:166. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 115-220 of SEQ ID NO:166. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 221-311 of SEQ ID NO:166. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 312-408 of SEQ ID NO:166. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 27-220 of SEQ ID NO:166. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 115-311 of SEQ ID NO:166. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent binds afragment comprising amino acids 221-408 of SEQ ID NO:166. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsSEQ ID NO:169. In some embodiments, an ILT2-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:170. In some embodiments, anILT2-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:171. Insome embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds SEQ ID NO:172.

In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:2.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:3.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:4.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:5.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:6.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:7.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:16.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:17.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:18.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:19.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:20.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:21.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:167.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:168.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:169.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:170.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:171.In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:172.

In some embodiments, an ILT2-binding agent or an ILT2/ILT4-binding agentbinds an epitope comprising amino acids within SEQ ID NO:2. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:3. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:4. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:5. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:6. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:7. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:16 In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:17. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:18. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:19. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:20. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:21. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:167 In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:168. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:169. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:170. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:171. In someembodiments, an ILT2-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:172.

In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds ILT4 or a fragment of ILT4. In some embodiments, a fragment ofILT4 comprises the extracellular domain of ILT4. In some embodiments, afragment of ILT4 comprises one or more of the Ig-like C2 type domains(e.g., D1, D2, D3, and/or D4). In some embodiments, a fragment of ILT4comprises D1 and D2. In some embodiments, a fragment of ILT4 comprisesD2 and D3. In some embodiments, a fragment of ILT4 comprises D3 and D4.In some embodiments, a fragment of ILT4 comprises D1, D2, and D3. Insome embodiments, a fragment of ILT4 comprises D2, D3, and D4. In someembodiments, a fragment of ILT4 comprises one or more of the Ig-like C2type domains and the stem region. In some embodiments, a fragment ofILT4 comprises D4-stem, D3-D4-stem, or D2-D3-D4-stem. In someembodiments, the extracellular domain of human ILT4 comprises aminoacids 22-461 of SEQ ID NO:8. In some embodiments, D1 of human ILT4comprises amino acids 27-110 of SEQ ID NO:8. In some embodiments, D2 ofhuman ILT4 comprises amino acids 111-229 of SEQ ID NO:8. In someembodiments, D3 of human ILT4 comprises amino acids 230-318 of SEQ IDNO:8. In some embodiments, D4 of human ILT4 comprises amino acids330-419 of SEQ ID NO:8. In some embodiments, D1-D2 of human ILT4comprises amino acids 27-229 of SEQ ID NO:8. In some embodiments, D2-D3of human ILT4 comprises amino acids 111-318 of SEQ ID NO:8. In someembodiments, D3-D4 of human ILT4 comprises amino acids 230-419 of SEQ IDNO:8. In some embodiments, D1-D2-D3 of human ILT4 comprises amino acids27-318 of SEQ ID NO:8. In some embodiments, D2-D3-D4 of human ILT4comprises amino acids 111-419 of SEQ ID NO:8. In some embodiments,D4-stem of human ILT4 comprises amino acids 330-461 of SEQ ID NO:8. Insome embodiments, D3-D4-stem of human ILT4 comprises amino acids 230-461of SEQ ID NO:8. In some embodiments, D2-D3-D4-stem of human ILT4comprises amino acids 111-461 of SEQ ID NO:8.

In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds a fragment of ILT4. In some embodiments, an ILT4-binding agent oran ILT2/ILT4-binding agent binds within a specific region of ILT4. Insome embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds within the extracellular domain of ILT4. In some embodiments, anILT4-binding agent or an ILT2/ILT4-binding agent binds within the D1domain of ILT4. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds within the D2 domain of ILT4. In someembodiments, an ILT4-binding agent or an ILT2/ILT4-binding agent bindswithin the D3 domain of ILT4. In some embodiments, an ILT4-binding agentor an ILT2/ILT4-binding agent binds within the D4 domain of ILT4. Insome embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds within the D4-stem region of ILT4. In some embodiments, anILT4-binding agent or an ILT2/ILT4-binding agent binds within the D1-D2domains of ILT4. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds within the D2-D3 domains of ILT4. In someembodiments, an ILT4-binding agent or an ILT2/ILT4-binding agent bindswithin the D3-D4 domains of ILT4. In some embodiments, an ILT4-bindingagent or an ILT2/ILT4-binding agent binds within the D1-D2-D3 domains ofILT4. In some embodiments, an ILT4-binding agent or an ILT2/ILT4-bindingagent binds within the D2-D3-D4 domains of ILT4. In some embodiments, anILT4-binding agent or an ILT2/ILT4-binding agent binds an epitope onILT4. In some embodiments, an ILT4-binding agent or an ILT2/ILT4-bindingagent binds a conformational epitope on ILT4. In some embodiments, anILT4-binding agent does not bind other human LILRB proteins (e.g., ILT2,ILT3, ILT5, or LILRB5). In some embodiments, an ILT2/ILT4-binding agentdoes not bind other human LILRB proteins (e.g., ILT3, ILT5, or LILRB5).In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentdoes not bind one or more of the human LILRA proteins (e.g., LILRA1,LILRA2, LILRA4, LILRA5, or LILRA6). In some embodiments, an ILT4-bindingagent or an ILT2/ILT4-binding agent does not bind LILRA2, LILRA4,LILRA5, or LILRA6.

In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds human ILT4. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:8. In some embodiments, anILT4-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:9. Insome embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds SEQ ID NO:10. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds a fragment comprising amino acids 22-461of SEQ ID NO:8. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds a fragment comprising amino acids 27-110of SEQ ID NO:8. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds a fragment comprising amino acids 111-229of SEQ ID NO:8. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds a fragment comprising amino acids 230-318of SEQ ID NO:8. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds a fragment comprising amino acids 330-419of SEQ ID NO:8. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds a fragment comprising amino acids 27-229of SEQ ID NO:8. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds a fragment comprising amino acids 111-318of SEQ ID NO:8. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds a fragment comprising amino acids 230-419of SEQ ID NO:8. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:11. In some embodiments, anILT4-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:12. Insome embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds SEQ ID NO:13. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:14. In some embodiments, anILT4-binding agent or an ILT2/ILT4-binding agent binds SEQ ID NO:11 andSEQ ID NO:12. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:12 and SEQ ID NO:13. In someembodiments, an ILT4-binding agent or an ILT2/ILT4-binding agent bindsSEQ ID NO:13 and SEQ ID NO:14. In some embodiments, an ILT4-bindingagent or an ILT2/ILT4-binding agent binds SEQ ID NO:11, SEQ ID NO:12,and SEQ ID NO:13. In some embodiments, an ILT4-binding agent or anILT2/ILT4-binding agent binds SEQ ID NO:12, SEQ ID NO:13, and SEQ IDNO:14.

In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:9.In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:10.In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:11.In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:12.In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:13.In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds a polypeptide comprising the amino acid sequence of SEQ ID NO:14.

In some embodiments, an ILT4-binding agent or an ILT2/ILT4-binding agentbinds an epitope comprising amino acids within SEQ ID NO:9. In someembodiments, an ILT4-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:10. In someembodiments, an ILT4-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:11. In someembodiments, an ILT4-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:12. In someembodiments, an ILT4-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:13. In someembodiments, an ILT4-binding agent or an ILT2/ILT4-binding agent bindsan epitope comprising amino acids within SEQ ID NO:14.

In some embodiments, an ILT-binding agent binds human ILT2, human ILT4,or both human ILT2/ILT4, and has at least one or more of the followingproperties: (i) binds rhesus ILT2; (ii) binds cyno ILT2; (iii) does notbind ILT3, ILT5, and LILRB5; (iv) does not bind LILRA2, LILRA4, LILRA5,and LILRA6; (v) is an ILT2 antagonist; (vi) is an ILT4 antagonist, (vii)inhibits ILT2 activity; (viii) inhibits ILT4 activity; (ix) inhibitsILT2 signaling in cells that express ILT2; (x) inhibits ILT4 signalingin cells that express ILT4; (xi) inhibits binding of ILT2 to MHC Imolecules; (xii) inhibits binding of ILT4 to MHC I molecules; (xiii)inhibits ILT2-induced suppression of myeloid cells; (xiv) inhibitsILT4-induced suppression of myeloid cells; (xv) inhibits ILT2-inducedsuppression of myeloid cell activity; (xvi) inhibits ILT4-inducedsuppression of myeloid cell activity; (xvii) restores FcR activation inmyeloid cells; (xviii) enhances NK cell activity; (xix) enhances CTLactivity; and/or (xx) enhances macrophage phagocytosis.

In some embodiments, an ILT-binding agent is an antibody. In someembodiments, an ILT2-binding agent is an antibody. In some embodiments,an ILT4-binding agent is an antibody. In some embodiments, anILT2/ILT4-binding agent is an antibody. In some embodiments, anILT-binding agent is an anti-ILT2 antibody. In some embodiments, anILT-binding agent is an anti-ILT4 antibody. In some embodiments, anILT-binding agent is an anti-ILT2/ILT4 antibody. In some embodiments,the antibody is a recombinant antibody. In some embodiments, theantibody is a monoclonal antibody. In some embodiments, the antibody isa chimeric antibody. In some embodiments, the antibody is a humanizedantibody. In some embodiments, the antibody is a human antibody. In someembodiments, the antibody is an IgG antibody. In some embodiments, theantibody is an IgG1 antibody. In some embodiments, the antibody is anIgG2 antibody. In some embodiments, the antibody is an IgG3 antibody. Insome embodiments, the antibody is an IgG4 antibody. In some embodiments,the antibody comprises an IgG heavy chain. In some embodiments, theantibody comprises an IgG1 heavy chain. In some embodiments, theantibody comprises an IgG2 heavy chain. In some embodiments, theantibody comprises an IgG4 heavy chain. In some embodiments, theantibody comprises a human IgG heavy chain. In some embodiments, theantibody comprises a human IgG1 heavy chain. In some embodiments, theantibody comprises a human IgG2 heavy chain. In some embodiments, theantibody comprises a human IgG4 heavy chain. In some embodiments, theantibody comprises a kappa light chain. In some embodiments, theantibody comprises a kappa light chain constant region. In someembodiments, the antibody comprises a human kappa light chain constantregion. In some embodiments, the antibody comprises a lambda lightchain. In some embodiments, the antibody comprises a lambda light chainconstant region. In some embodiments, the antibody comprises a humanlambda light chain constant region. In some embodiments, the antibody isan antibody fragment comprising at least one antigen-binding site. Insome embodiments, the antibody is a scFv. In some embodiments, theantibody is a disulfide-linked scFv. In some embodiments, the antibodyis a disulfide-linked sc(Fv)₂. In some embodiments, the antibody is aFab, Fab′, or a F(ab)₂ antibody. In some embodiments, the antibody is adiabody. In some embodiments, the antibody is a nanobody. In someembodiments, the antibody is a monospecific antibody. In someembodiments, the antibody is a bispecific antibody. In some embodiments,the antibody is a multispecific antibody. In some embodiments, theantibody is a monovalent antibody. In some embodiments, the antibody isa bivalent antibody. In some embodiments, the antibody is a tetravalentantibody.

In some embodiments, the antibody is isolated. In some embodiments, theantibody is substantially pure.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) is a polyclonalantibody. Polyclonal antibodies can be prepared by any method known tothose of skill in the art. In some embodiments, polyclonal antibodiesare produced by immunizing an animal (e.g., a rabbit, rat, mouse, goat,donkey) with an antigen of interest (e.g., a purified peptide fragment,a recombinant protein, or a fusion protein) using multiple subcutaneousor intraperitoneal injections. In some embodiments, the antigen isconjugated to a carrier such as keyhole limpet hemocyanin (KLH), serumalbumin, bovine thyroglobulin, or soybean trypsin inhibitor. The antigen(with or without a carrier protein) is diluted in sterile saline andusually combined with an adjuvant (e.g., Complete or Incomplete Freund'sAdjuvant) to form a stable emulsion. After a period of time, polyclonalantibodies are recovered from the immunized animal (e.g., from blood orascites). In some embodiments, the polyclonal antibodies are purifiedfrom serum or ascites according to standard methods in the artincluding, but not limited to, affinity chromatography, ion-exchangechromatography, gel electrophoresis, and/or dialysis.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) is a monoclonalantibody. Monoclonal antibodies can be prepared by any method known tothose of skill in the art. In some embodiments, monoclonal antibodiesare prepared using hybridoma methods known to one of skill in the art.For example, using a hybridoma method, a mouse, rat, rabbit, hamster, orother appropriate host animal, is immunized as described above. In someembodiments, lymphocytes are immunized in vitro. In some embodiments,the immunizing antigen is a human protein or a fragment thereof. In someembodiments, the immunizing antigen is a mouse protein or a fragmentthereof. In some embodiments, the immunizing antigen is a rhesus proteinor a fragment thereof. In some embodiments, the immunizing antigen is acyno protein or a fragment thereof. In some embodiments, the immunizingantigen is a combination of two or more (e.g., 2, 3, 4) related proteinsor fragments thereof.

Following immunization, lymphocytes are isolated and fused with asuitable myeloma cell line using, for example, polyethylene glycol. Thehybridoma cells are selected using specialized media as known in the artand unfused lymphocytes and myeloma cells do not survive the selectionprocess. Hybridomas that produce monoclonal antibodies against a chosenantigen can be identified by a variety of methods including, but notlimited to, immunoprecipitation, immunoblotting, and in vitro bindingassays (e.g., flow cytometry, FACS, ELISA, SPR (e.g., Biacore), andradioimmunoassay). Once hybridoma cells that produce antibodies of thedesired specificity, affinity, and/or activity are identified, theclones may be subcloned by limiting dilution techniques. In someembodiments, high-throughput methods are used to distribute single cellhybridoma cells into plates. The hybridomas can be propagated either inin vitro culture using standard methods or in vivo as ascites tumors inan animal. The monoclonal antibodies can be purified from the culturemedium or ascites fluid according to standard methods in the artincluding, but not limited to, affinity chromatography, ion-exchangechromatography, gel electrophoresis, and dialysis.

In some embodiments, monoclonal antibodies are made using recombinantDNA techniques as known to one skilled in the art. For example, thepolynucleotides encoding an antibody are isolated from mature B-cells orhybridoma cells, such as by RT-PCR using oligonucleotide primers thatspecifically amplify the genes encoding the heavy and light chains ofthe antibody, and their sequence is determined using standardtechniques. The isolated polynucleotides encoding the heavy and lightchains are then cloned into suitable expression vectors which producethe monoclonal antibodies when transfected into host cells such as E.coli, simian COS cells, Chinese hamster ovary (CHO) cells, or myelomacells that do not otherwise produce immunoglobulin proteins.

In some embodiments, recombinant monoclonal antibodies are isolated fromphage display libraries expressing variable domains or CDRs of a desiredspecies. Screening of phage libraries can be accomplished by varioustechniques known in the art.

In some embodiments, a monoclonal antibody is modified by usingrecombinant DNA technology to generate alternative antibodies. In someembodiments, the constant domains of the light chain and heavy chain ofa mouse monoclonal antibody are substituted for constant regions of ahuman antibody to generate a chimeric antibody. In some embodiments, theconstant regions are truncated or removed to generate a desired antibodyfragment of a monoclonal antibody. In some embodiments, site-directed orhigh-density mutagenesis of the variable region(s) is used to optimizespecificity and affinity of a monoclonal antibody.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) is a humanizedantibody. Various methods for generating humanized antibodies are knownin the art. In some embodiments, a humanized antibody comprises one ormore amino acid residues that have been introduced into it from a sourcethat is non-human. In some embodiments, humanization is performed bysubstituting one or more non-human CDR sequences for the correspondingCDR sequences of a human antibody. In some embodiments, the humanizedantibodies are constructed by substituting all six CDRs of a non-humanantibody (e.g., a mouse antibody) for the corresponding CDRs of a humanantibody.

The choice of which human heavy chain variable region and/or light chainvariable region to use for generating humanized antibodies can be madebased on a variety of factors and by a variety of methods known in theart. In some embodiments, the “best-fit” method is used where thesequence of the variable region of a non-human (e.g., rodent) antibodyis screened against the entire library of known human variable regionsequences. The human sequence that is most similar to that of thenon-human (e.g., rodent) sequence is selected as the human variableregion framework for the humanized antibody. In some embodiments, aparticular variable region framework derived from a consensus sequenceof all human antibodies of a particular subgroup of light or heavychains is selected as the variable region framework. In someembodiments, the variable region framework sequence is derived from theconsensus sequences of the most abundant human subclasses. In someembodiments, human germline genes are used as the source of the variableregion framework sequences.

Other methods for humanization include, but are not limited to, a methodcalled “superhumanization” which is described as the direct transfer ofCDRs to a human germline framework, a method termed Human String Content(HSC) which is based on a metric of “antibody humanness”, methods basedon generation of large libraries of humanized variants (including phage,ribosomal, and yeast display libraries), and methods based on frameworkregion shuffling.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) is a humanantibody. Human antibodies can be prepared using various techniquesknown in the art. In some embodiments, human antibodies are generatedfrom immortalized human B lymphocytes immunized in vitro. In someembodiments, human antibodies are generated from lymphocytes isolatedfrom an immunized individual. In any case, cells that produce anantibody directed against a target antigen can be generated andisolated. In some embodiments, a human antibody is selected from a phagelibrary, where that phage library expresses human antibodies.Alternatively, phage display technology may be used to produce humanantibodies and antibody fragments in vitro, from immunoglobulin variableregion gene repertoires from unimmunized human donors. Techniques forthe generation and use of antibody phage libraries are well known in theart. Once antibodies are identified, affinity maturation strategiesknown in the art, including but not limited to, chain shuffling andsite-directed mutagenesis, may be employed to generate higher affinityhuman antibodies. In some embodiments, human antibodies are produced intransgenic mice that contain human immunoglobulin loci. Uponimmunization these mice are capable of producing the full repertoire ofhuman antibodies in the absence of endogenous immunoglobulin production.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) is an antibodyfragment. As used herein, the term “antibody fragment” refers to amolecule other than an intact antibody that comprises a portion of anantibody and generally at least one antigen-binding site. Examples ofantibody fragments include, but are not limited to, Fab, Fab′, F(ab′)2,Fv, single chain antibody molecules (e.g., scFv), disulfide-linked scFv(dsscFv), nanobodies, diabodies, tribodies, tetrabodies, minibodies,dual variable domain antibodies (DVD), single variable domain antibodies(e.g., camelid antibodies), and multispecific antibodies formed fromantibody fragments.

In some embodiments, an ILT-binding agent is a scFv antibody. In someembodiments, the scFv is a disulfide-linked scFv (dsscFv), which is ascFv comprising an engineered disulfide bond between the light chainvariable region and heavy chain variable region of the scFv. In someembodiments, the disulfide bond increases stability of the scFvmolecule. In some embodiments, the disulfide bond increasesthermostability of the scFv molecule.

In some embodiments, an ILT-binding agent is a Fv. In some embodiments,an ILT-binding agent is a Fab. In some embodiments, an ILT-binding agentis a F(ab′)₂. In some embodiments, an ILT-binding agent is a F(ab′).

Antibody fragments can be made by various techniques, including but notlimited to proteolytic digestion of an intact antibody. The antibodyfragments described herein can be produced using recombinanttechnologies known in the art (e.g., E. coli or phage expression).

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) is a bispecificantibody. Bispecific antibodies are capable of recognizing and bindingat least two different antigens or epitopes. The different epitopes caneither be within the same molecule (e.g., two epitopes on ILT2) or ondifferent molecules (e.g., one epitope on ILT2 and a second epitope on adifferent target). In some embodiments, a bispecific antibody hasenhanced potency as compared to an individual antibody or to acombination of more than one antibody. In some embodiments, a bispecificantibody has reduced toxicity as compared to an individual antibody orto a combination of more than one antibody. It is known to those ofskill in the art that any therapeutic agent may have uniquepharmacokinetics (PK) (e.g., circulating half-life). In someembodiments, a bispecific antibody has the ability to synchronize the PKof two active binding agents wherein the two individual binding agentshave different PK profiles. In some embodiments, a bispecific antibodyhas the ability to concentrate the actions of two agents in a commonarea (e.g., tissue) in a subject. In some embodiments, a bispecificantibody has the ability to concentrate the actions of two agents to acommon target (e.g., a specific cell type). In some embodiments, abispecific antibody has the ability to target the actions of two agentsto more than one biological pathway or function. In some embodiments, abispecific antibody has the ability to target two different cells andbring them closer together.

In some embodiments, a bispecific antibody has decreased toxicity and/orside effects. In some embodiments, a bispecific antibody has decreasedtoxicity and/or side effects as compared to a mixture of the twoindividual antibodies or the antibodies as single agents. In someembodiments, a bispecific antibody has an increased therapeutic index.In some embodiments, a bispecific antibody has an increased therapeuticindex as compared to a mixture of the two individual antibodies or theantibodies as single agents.

Many techniques for making bispecific antibodies are known to thoseskilled in the art. In some embodiments, a bispecific antibody comprisesheavy chain constant regions with modifications in the amino acids thatare part of the interface between the two heavy chains. Thesemodifications are made to enhance heterodimer formation and generallyreduce or eliminate homodimer formation. In some embodiments, thebispecific antibody is generated using a knobs-into-holes (KIH)strategy. In some embodiments, the bispecific antibody comprises varianthinge regions incapable of forming disulfide linkages between identicalheavy chains (e.g., reduce homodimer formation). In some embodiments,the bispecific antibody comprises heavy chains with changes in aminoacids that result in altered electrostatic interactions. In someembodiments, the bispecific antibodies comprise heavy chains withchanges in amino acids that result in altered hydrophobic/hydrophilicinteractions.

Bispecific antibodies can be intact antibodies or antibody fragmentscomprising antigen-binding sites.

In some embodiments, an ILT-binding agent is an antibody that bindsILT2. In some embodiments, an anti-ILT antibody binds human ILT2. Insome embodiments, an anti-ILT antibody binds cyno ILT2. In someembodiments, an anti-ILT antibody binds rhesus ILT2. In someembodiments, an anti-ILT antibody binds human ILT2 and cyno ILT2. Insome embodiments, an anti-ILT antibody binds human ILT2 and rhesus ILT2.In some embodiments, an anti-ILT antibody binds human ILT2, rhesus ILT2,and cyno ILT2. In some embodiments, an anti-ILT2 antibody binds an ILT2epitope. In some embodiments, an anti-ILT2 antibody binds an ILT2epitope within the extracellular domain of human ILT2. In someembodiments, an anti-ILT2 antibody binds an ILT2 epitope within theextracellular domain of cyno ILT2. In some embodiments, an anti-ILT2antibody binds an ILT2 epitope within the extracellular domain of rhesusILT2. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 24-461 of SEQ ID NO:1. In some embodiments, ananti-ILT2 antibody binds an epitope comprising at least one amino acid(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within amino acids 27-115 of SEQ IDNO:1. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 116-221 of SEQ ID NO:1. In some embodiments, ananti-ILT2 antibody binds an epitope comprising at least one amino acid(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within amino acids 222-312 of SEQ IDNO:1. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 313-409 of SEQ ID NO:1. In some embodiments, ananti-ILT2 antibody binds an epitope comprising amino acids within SEQ IDNO:3. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising amino acids within SEQ ID NO:4. In some embodiments, ananti-ILT2 antibody binds an epitope comprising amino acids within SEQ IDNO:5. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising amino acids within SEQ ID NO:6. In some embodiments, ananti-ILT2 antibody binds an epitope comprising amino acids within SEQ IDNO:7. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 24-460 of SEQ ID NO:15. In some embodiments, ananti-ILT2 antibody binds an epitope comprising at least one amino acid(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within amino acids 27-114 of SEQ IDNO:15. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 115-220 of SEQ ID NO:15. In some embodiments, ananti-ILT2 antibody binds an epitope comprising at least one amino acid(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within amino acids 221-311 of SEQ IDNO:15. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 312-408 of SEQ ID NO:15. In some embodiments, ananti-ILT2 antibody binds an epitope comprising amino acids within SEQ IDNO:17. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising amino acids within SEQ ID NO:18. In some embodiments, ananti-ILT2 antibody binds an epitope comprising amino acids within SEQ IDNO:19. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising amino acids within SEQ ID NO:20. In some embodiments, ananti-ILT2 antibody binds an epitope comprising amino acids within SEQ IDNO:21. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 24-461 of SEQ ID NO:166. In some embodiments, ananti-ILT2 antibody binds an epitope comprising at least one amino acid(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within amino acids 27-114 of SEQ IDNO:166. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 115-220 of SEQ ID NO:166. In some embodiments, ananti-ILT2 antibody binds an epitope comprising at least one amino acid(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within amino acids 221-311 of SEQ IDNO:166. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 312-408 of SEQ ID NO:166. In some embodiments, ananti-ILT2 antibody binds an epitope comprising amino acids within SEQ IDNO:168. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising amino acids within SEQ ID NO:169. In some embodiments, ananti-ILT2 antibody binds an epitope comprising amino acids within SEQ IDNO:170. In some embodiments, an anti-ILT2 antibody binds an epitopecomprising amino acids within SEQ ID NO:171. In some embodiments, ananti-ILT2 antibody binds an epitope comprising amino acids within SEQ IDNO:172. In some embodiments, the epitope is a conformational epitope. Insome embodiments, the epitope is a linear epitope.

In some embodiments, an ILT-binding agent is an antibody that bindsILT4. In some embodiments, an anti-ILT antibody binds human ILT4. Insome embodiments, an anti-ILT4 antibody binds an ILT4 epitope. In someembodiments, an anti-ILT4 antibody binds an ILT4 epitope within theextracellular domain of human ILT4. In some embodiments, an anti-ILT4antibody binds an epitope comprising at least one amino acid (e.g., 1,2, 3, 4, 5, 6, 7, 8, 9) within amino acids 22-461 of SEQ ID NO:8. Insome embodiments, an anti-ILT4 antibody binds an epitope comprising atleast one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within aminoacids 27-110 of SEQ ID NO:8. In some embodiments, an anti-ILT4 antibodybinds an epitope comprising at least one amino acid (e.g., 1, 2, 3, 4,5, 6, 7, 8, 9) within amino acids 111-229 of SEQ ID NO:8. In someembodiments, an anti-ILT4 antibody binds an epitope comprising at leastone amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within amino acids230-318 of SEQ ID NO:8. In some embodiments, an anti-ILT4 antibody bindsan epitope comprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6,7, 8, 9) within amino acids 330-419 of SEQ ID NO:8. In some embodiments,an anti-ILT4 antibody binds an epitope comprising amino acids within SEQID NO:9. In some embodiments, an anti-ILT4 antibody binds an epitopecomprising amino acids within SEQ ID NO:10. In some embodiments, ananti-ILT4 antibody binds an epitope comprising amino acids within SEQ IDNO:11. In some embodiments, an anti-ILT4 antibody binds an epitopecomprising amino acids within SEQ ID NO:12. In some embodiments, ananti-ILT4 antibody binds an epitope comprising amino acids within SEQ IDNO:13. In some embodiments, an anti-ILT4 antibody binds an epitopecomprising amino acids within SEQ ID NO:14. In some embodiments, theepitope is a conformational epitope. In some embodiments, the epitope isa linear epitope.

In some embodiments, an ILT-binding agent is an antibody that binds ILT2and ILT4. It is understood by those of skill in the art that an antibodythat binds ILT2 and ILT4, described as a dual binder, comprises at leastone antigen-binding site that binds an epitope on both ILT2 and ILT4, incontrast to a bispecific antibody which would comprise oneantigen-binding site that binds an epitope on ILT2 and a secondantigen-binding site that binds a different epitope on ILT4. In someembodiments, an anti-ILT2/ILT4 antibody binds human ILT2 and human ILT4.In some embodiments, anti-ILT2/ILT4 antibody binds human ILT2, humanILT4, cyno ILT2, and rhesus ILT2. In some embodiments, an anti-ILT2/ILT4antibody binds an ILT2 epitope and ILT4 epitope. In some embodiments, ananti-ILT2/ILT4 antibody binds an epitope within the extracellular domainof human ILT2 and an epitope within the extracellular domain of humanILT4, wherein the ILT2 epitope and the ILT4 epitope are the same oressentially the same. In some embodiments, an anti-ILT2/ILT4 antibodybinds an ILT2 epitope within the extracellular domain of human ILT2, anILT4 epitope within the extracellular domain of human ILT4, an ILT2epitope within the extracellular domain of cyno ILT2, and an ILT2epitope within the extracellular domain of rhesus ILT2. In someembodiments, an anti-ILT2/ILT4 antibody binds an epitope comprising atleast one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within aminoacids 24-461 of SEQ ID NO:1 and the same or essentially the same epitopewithin amino acids 22-461 of SEQ ID NO:8. In some embodiments, ananti-ILT2/ILT4 antibody binds an epitope comprising at least one aminoacid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within amino acids 27-115 of SEQID NO:1 and the same or essentially the same epitope within amino acids27-110 of SEQ ID NO:8. In some embodiments, an anti-ILT2/ILT4 antibodybinds an epitope comprising at least one amino acid (e.g., 1, 2, 3, 4,5, 6, 7, 8, 9) within amino acids 116-221 of SEQ ID NO:1 and the same oressentially the same epitope within amino acids 111-229 of SEQ ID NO:8.In some embodiments, an anti-ILT2/ILT4 antibody binds an epitopecomprising at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9)within amino acids 222-312 of SEQ ID NO:1 and the same or essentiallythe same epitope within amino acids 230-318 of SEQ ID NO:8. In someembodiments, an anti-ILT2/ILT4 antibody binds an epitope comprising atleast one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9) within aminoacids 313-409 of SEQ ID NO:1 and the same or essentially the sameepitope within amino acids 330-419 of SEQ ID NO:8. In some embodiments,the epitope is a conformational epitope. In some embodiments, theepitope is a linear epitope.

In some embodiments, an ILT-binding agent is an anti-ILT2 antibody, ananti-ILT4 antibody, or an anti-ILT2/ILT4 antibody described herein. Insome embodiments, the ILT-binding agent is a variant of an anti-ILT2antibody, an anti-ILT4 antibody, or an anti-ILT2/ILT4 antibody describedherein. In some embodiments, a variant of an anti-ILT antibody comprisesone to thirty amino acid substitutions. In some embodiments, a variantof the anti-ILT antibody comprises one to twenty-five amino acidsubstitutions. In some embodiments, a variant of the anti-ILT antibodycomprises one to twenty amino acid substitutions. In some embodiments, avariant of the anti-ILT antibody comprises one to fifteen amino acidsubstitutions. In some embodiments, a variant of the anti-ILT antibodycomprises one to ten amino acid substitutions. In some embodiments, avariant of the anti-ILT antibody comprises one to five amino acidsubstitutions. In some embodiments, the variant of the anti-ILT antibodycomprises one to three amino acid substitutions. In some embodiments,the amino acid substitution(s) is in a CDR of the antibody. In someembodiments, the amino acid substitution(s) is not in a CDR of theantibody. In some embodiments, the amino acid substitution(s) is in aframework region of the antibody. In some embodiments, the amino acidsubstitution(s) is a conservative amino acid substitution.

CDRs of an antibody are defined using a variety of methods/systems bythose skilled in the art. These systems and/or definitions have beendeveloped and refined over a number of years and include Kabat, Chothia,IMGT, AbM, and Contact. The Kabat definition is based on sequencevariability and is commonly used. The Chothia definition is based on thelocation of the structural loop regions. The IMGT system is based onsequence variability and location within the structure of the variabledomain. The AbM definition is a compromise between Kabat and Chothia.The Contact definition is based on analyses of the available antibodycrystal structures. An Exemplary system is a combination of Kabat andChothia. Software programs (e.g., abYsis) are available and known tothose of skill in the art for analysis of antibody sequence anddetermination of CDRs.

The specific CDR sequences defined herein are generally based on acombination of Kabat and Chothia definitions (Exemplary definition).However, it will be understood that reference to a heavy chain variableregion CDR or CDRs and/or a light chain variable region CDR or CDRs of aspecific antibody will encompass all CDR definitions as known to thoseof skill in the art.

In some embodiments, an anti-ILT antibody described herein comprises thesix CDRs of antibody 27F9, 47C8, 48A5, 47H6, Hz47H6.v2, 51A1, 64A12,Hz64A12, 73C4, 73D1, or Hz73D1.v1 based on the Kabat definition. In someembodiments, an anti-ILT antibody described herein comprises the sixCDRs of antibody 27F9, 47C8, 48A5, 47H6, Hz47H6.v2, 51A1, 64A12,Hz64A12, 73C4, 73D1, or Hz73D1.v1 based on the Chothia definition. Insome embodiments, an anti-ILT antibody described herein comprises thesix CDRs of antibody 27F9, 47C8, 48A5, 47H6, Hz47H6.v2, 51A1, 64A12,Hz64A12, 73C4, 73D1, or Hz73D1.v1 based on the AbM definition. In someembodiments, an anti-ILT antibody described herein comprises the sixCDRs of antibody 27F9, 47C8, 48A5, 47H6, Hz47H6.v2, 51A1, 64A12,Hz64A12, 73C4, 73D1, or Hz73D1.v1 based on the IMGT definition. In someembodiments, an anti-ILT antibody described herein comprises the sixCDRs of antibody 27F9, 47C8, 48A5, 47H6, Hz47H6.v2, 51A1, 64A12,Hz64A12, 73C4, 73D1, or Hz73D1.v1 based on the Contact definition. Insome embodiments, an anti-ILT antibody described herein comprises thesix CDRs of antibody 27F9, 47C8, 48A5, 47H6, Hz47H6.v2, 51A1, 64A12,Hz64A12, 73C4, 73D1, or Hz73D1.v1 based on the Exemplary definition.

In some embodiments, an ILT-binding agent is an anti-ILT antibody (e.g.,an anti-ILT2 antibody, an anti-ILT4 antibody, or an anti-ILT2/ILT4antibody) that comprises one, two, three, four, five, and/or six CDRs ofany one of the antibodies described herein. In some embodiments, ananti-ILT2 antibody comprises (i) a heavy chain variable regioncomprising one, two, and/or three heavy chain variable region CDRs fromTable 1, and/or (ii) a light chain variable region comprising one, two,and/or three light chain variable region CDRs from Table 1. In someembodiments, an anti-ILT4 antibody comprises (i) a heavy chain variableregion comprising one, two, and/or three heavy chain variable regionCDRs from Table 2, and/or (ii) a light chain variable region comprisingone, two, and/or three light chain variable region CDRs from Table 2. Insome embodiments, an anti-ILT4 antibody comprises (i) a heavy chainvariable region comprising one, two, and/or three heavy chain variableregion CDRs from Table 3, and/or (ii) a light chain variable regioncomprising one, two, and/or three light chain variable region CDRs fromTable 3. In some embodiments, an anti-ILT2/ILT4 antibody comprises (i) aheavy chain variable region comprising one, two, and/or three heavychain variable region CDRs from Table 4A or Table 4B, and/or (ii) alight chain variable region comprising one, two, and/or three lightchain variable region CDRs from Table 4A or Table 4B. In someembodiments, an anti-ILT2/ILT4 antibody comprises (i) a heavy chainvariable region comprising one, two, and/or three heavy chain variableregion CDRs from Table 5, and/or (ii) a light chain variable regioncomprising one, two, and/or three light chain variable region CDRs fromTable 5. In some embodiments, an anti-ILT2/ILT4 antibody comprises (i) aheavy chain variable region comprising one, two, and/or three heavychain variable region CDRs from Table 6A or Table 6B, and/or (ii) alight chain variable region comprising one, two, and/or three lightchain variable region CDRs from Table 6A or Table 6B. In someembodiments, an anti-ILT2/ILT4 antibody comprises (i) a heavy chainvariable region comprising one, two, and/or three heavy chain variableregion CDRs from Table 7, and/or (ii) a light chain variable regioncomprising one, two, and/or three light chain variable region CDRs fromTable 7. In some embodiments, an anti-ILT2/ILT4 antibody comprises (i) aheavy chain variable region comprising one, two, and/or three heavychain variable region CDRs from Table 8A or Table 8B, and/or (ii) alight chain variable region comprising one, two, and/or three lightchain variable region CDRs from Table 8A or Table 8B. In someembodiments, an anti-ILT2 antibody comprises (i) a heavy chain variableregion comprising three heavy chain variable region CDRs from Table 1,and (ii) a light chain variable region comprising three light chainvariable region CDRs from Table 1. In some embodiments, an anti-ILT4antibody comprises (i) a heavy chain variable region comprising threeheavy chain variable region CDRs from Table 2, and (ii) a light chainvariable region comprising three light chain variable region CDRs fromTable 2. In some embodiments, an anti-ILT4 antibody comprises (i) aheavy chain variable region comprising three heavy chain variable regionCDRs from Table 3, and (ii) a light chain variable region comprisingthree light chain variable region CDRs from Table 3. In someembodiments, an anti-ILT2/ILT4 antibody comprises (i) a heavy chainvariable region comprising three heavy chain variable region CDRs fromTable 4A, and (ii) a light chain variable region comprising three lightchain variable region CDRs from Table 4A. In some embodiments, ananti-ILT2/ILT4 antibody comprises (i) a heavy chain variable regioncomprising three heavy chain variable region CDRs from Table 4B, and(ii) a light chain variable region comprising three light chain variableregion CDRs from Table 4B. In some embodiments, an anti-ILT2/ILT4antibody comprises (i) a heavy chain variable region comprising threeheavy chain variable region CDRs from Table 5, and (ii) a light chainvariable region comprising three light chain variable region CDRs fromTable 5. In some embodiments, an anti-ILT2/ILT4 antibody comprises (i) aheavy chain variable region comprising three heavy chain variable regionCDRs from Table 6A, and (ii) a light chain variable region comprisingthree light chain variable region CDRs from Table 6A. In someembodiments, an anti-ILT2/ILT4 antibody comprises (i) a heavy chainvariable region comprising three heavy chain variable region CDRs fromTable 6B, and (ii) a light chain variable region comprising three lightchain variable region CDRs from Table 6B. In some embodiments, ananti-ILT2/ILT4 antibody comprises (i) a heavy chain variable regioncomprising three heavy chain variable region CDRs from Table 7, and (ii)a light chain variable region comprising three light chain variableregion CDRs from Table 7. In some embodiments, an anti-ILT2/ILT4antibody comprises (i) a heavy chain variable region comprising threeheavy chain variable region CDRs from Table 8A, and (ii) a light chainvariable region comprising three light chain variable region CDRs fromTable 8B. In some embodiments, an anti-ILT2/ILT4 antibody comprises (i)a heavy chain variable region comprising three heavy chain variableregion CDRs from Table 8B, and (ii) a light chain variable regioncomprising three light chain variable region CDRs from Table 8B.

TABLE 1 Anti-ILT2 Antibody 27F9 Sequences Exemplary Chothia AbM KabatContact Heavy Chain GFSLTNYGVS GFSLTNY GFSLTNYGVS NYGVS TNYGVS variable(SEQ ID NO: 22) (SEQ ID NO: 28) (SEQ ID NO: 22) (SEQ ID NO: 31)(SEQ ID NO: 32) region CDR1 Heavy Chain IIWGDGSTNYHSALIS WGDGS IIWGDGSTNIIWGDGSTNYHSALIS WLGIIWGDGSTN variable (SEQ ID NO: 23) (SEQ ID NO: 29)(SEQ ID NO: 30) (SEQ ID NO: 23) (SEQ ID NO: 33) region CDR2 Heavy ChainPNWDTYAMDF PNWDTYAMDF PNWDTYAMDF PNWDTYAMDF AKPNWDTYAMD variable(SEQ ID NO: 24) (SEQ ID NO: 24) (SEQ ID NO: 24) (SEQ ID NO: 24)(SEQ ID NO: 34) region CDR3 Light Chain RASQDISNFLN RASQDISNFLNRASQDISNFLN RASQDISNFLN SNFLNWY variable (SEQ ID NO: 25) (SEQ ID NO: 25)(SEQ ID NO: 25) (SEQ ID NO: 25) (SEQ ID NO: 35) region CDR1 Light ChainCTSKLHS CTSKLHS CTSKLHS CTSKLHS LLIYCTSKLH variable (SEQ ID NO: 26)(SEQ ID NO: 26) (SEQ ID NO: 26) (SEQ ID NO: 26) (SEQ ID NO: 36)region CDR2 Light Chain QQGNTLPPT QQGNTLPPT QQGNTLPPT QQGNTLPPT QQGNTLPPvariable (SEQ ID NO: 27) (SEQ ID NO: 27) (SEQ ID NO: 27) (SEQ ID NO: 27)(SEQ ID NO: 37) region CDR327F9 Heavy chain variable region (SEQ ID NO: 125)QVQLKESGPGLVAPSQSLSITCTVSGFSLTNYGVSWVRQPPGKGLEWLGIIWGDGSTNYHSALISRLSISKDNSKSQVFLKLNSLQADDTATYYCAKPNWDTYAMDFWGQGTSVTVSS27F9 Light chain variable region (SEQ ID NO: 126)DIQMTQTTSSLSASLGDRVTISCRASQDISNFLNWYQQKPDGTVKLLIYCTSKLHSGVPSRFSGSGSETDYSLTISNLEQEDIATYFCQQGNTLPPTFGGGTKLEII

TABLE 2 Anti-ILT4 Antibody 47C8 Sequences Exemplary Chothia AbM KabatContact Heavy Chain GYSFTGYYMEI GYSFTGY GYSFTGYYMEI GYYMH TGYYMHvariable region (SEQ ID NO: 38) (SEQ ID NO: 44) (SEQ ID NO: 38)(SEQ ID NO: 47) (SEQ ID NO: 48) CDR1 Heavy Chain RVYPNNGDTSYNQKF YPNNGDRVYPNNGDTS RVYPNNGDTSYNQKF WIGRVYPNNGDTS variable region KV(SEQ ID NO: 45) (SEQ ID NO: 46) KV (SEQ ID NO: 49) CDR2 (SEQ ID NO: 39)(SEQ ID NO: 39) Heavy Chain GATVVESLFAY GATVVESLFAY GATVVESLFAYGATVVESLFAY ARGATVVESLFA variable region (SEQ ID NO: 40) (SEQ ID NO: 40)(SEQ ID NO: 40) (SEQ ID NO: 40) (SEQ ID NO: 50) CDR3 Light ChainRASESVDNYGNNFLH RASESVDNYGNNFL RASESVDNYGNNFL RASESVDNYGNNFLHDNYGNNFLHWY variable region (SEQ ID NO: 41) H H (SEQ ID NO: 41)(SEQ ID NO: 51) CDR1 (SEQ ID NO: 41) (SEQ ID NO: 41) Light Chain RTSNLESRTSNLES RTSNLES RTSNLES LLIYRTSNLE variable region (SEQ ID NO: 42)(SEQ ID NO: 42) (SEQ ID NO: 42) (SEQ ID NO: 42) (SEQ ID NO: 52) CDR2Light Chain QQSNEDPYT QQSNEDPYT QQSNEDPYT QQSNEDPYT QQSNEDPYvariable region (SEQ ID NO: 43) (SEQ ID NO: 43) (SEQ ID NO: 43)(SEQ ID NO: 43) (SEQ ID NO: 53) CDR347C8 Heavy chain variable region (SEQ ID NO: 127)EVQLQQSGPDLVKPGASVKISCKASGYSFTGYYMEIWVKQSHGKSLEWIGRVYPNNGDTSYNQKFKVKAILTVDKSSSTAYMELRSLTSEDSAVYYCARGATVVESLFAYWGQGTLVTVSA47C8 Light chain variable region (SEQ ID NO: 128)DIVLTQSPASLAVSLGQRATISCRASESVDNYGNNFLHWYQQKPGQPPKLLIYRTSNLESGIPARFSGSGSRTDFTLTINPVEADDVATYYCQQSNEDPYTFGGGTKLEIK

TABLE 3 Anti-ILT4 Antibody 48A5 Sequences Exemplary Chothia AbM KabatContact Heavy Chain GYTFTNYGMN GYTFTNY GYTFTNYGMN NYGMN TNYGMNvariable region (SEQ ID NO: 54) (SEQ ID NO: 60) (SEQ ID NO: 54)(SEQ ID NO: 63) (SEQ ID NO: 64) CDR1 Heavy Chain WINTYIGEPIYADDFK NTYIGEWINTYIGEPI WINTYIGEPIYADDFK WMGWINTYIGEPI variable region G(SEQ ID NO: 61) (SEQ ID NO: 62) G (SEQ ID NO: 65) CDR2 (SEQ ID NO: 55)(SEQ ID NO: 55) Heavy Chain RSDYDGYAMDY RSDYDGYAMDY RSDYDGYAMDYRSDYDGYAMDY ARRSDYDGYAMD variable region (SEQ ID NO: 56) (SEQ ID NO: 56)(SEQ ID NO: 56) (SEQ ID NO: 56) (SEQ ID NO: 66) CDR3 Light ChainKSSQSLLYSGNQKNY KSSQSLLYSGNQKNY KSSQSLLYSGNQKNY KSSQSLLYSGNQKNYLYSGNQKNYLAWY variable region LA LA LA LA (SEQ ID NO: 67) CDR1(SEQ ID NO: 57) (SEQ ID NO: 57) (SEQ ID NO: 57) (SEQ ID NO: 57)Light Chain WASTRES WASTRES WASTRES WASTRES LLIYWASTRE variable region(SEQ ID NO: 58) (SEQ ID NO: 58) (SEQ ID NO: 58) (SEQ ID NO: 58)(SEQ ID NO: 68) CDR2 Light Chain QQHDSYPT QQHDSYPT QQHDSYPT QQHDSYPTQQHDSYP variable region (SEQ ID NO: 59) (SEQ ID NO: 59) (SEQ ID NO: 59)(SEQ ID NO: 59) (SEQ ID NO: 69) CDR348A5 Heavy chain variable region (SEQ ID NO: 129)QIQLVQSGPELKKPGETVKISCKASGYTFTNYGMNWVKQAPGKGLKWMGWINTYIGEPIYADDFKGRFAFSLETSASTAYLQINNLKNEDMATYFCARRSDYDGYAMDYWGQGTSVTVSS48A5 Light chain variable region (SEQ ID NO: 130)DIVMSQSPSSLAVSVGERVTMSCKSSQSLLYSGNQKNYLAWYQQKPGQSPKLLIYWASTRESGVPDRFTGSGSGTDFTLTISSVKAEDLAVYYCQQHDSYPTFGGGSRLEIK

TABLE 4A Anti-ILT2/1LT4 Antibody 47H6 Sequences Exemplary Chothia AbMKabat Contact Heavy Chain GYTFTDYYMN GYTFTDY GYTFTDYYMN DYYMN TDYYMNvariable (SEQ ID NO: 70) (SEQ ID NO: 76) (SEQ ID NO: 70) (SEQ ID NO: 79)(SEQ ID NO: 80) region CDR1 Heavy Chain DFNPNNGGTTYNQKF NPNNGGDFNPNNGGTT DFNPNNGGTTYNQKFE WIGDFNPNNGGTT variable EG (SEQ ID NO: 77)(SEQ ID NO: 78) G (SEQ ID NO: 81) region CDR2 (SEQ ID NO: 71)(SEQ ID NO: 71) Heavy Chain GRFYYGSLYSFDY GRFYYGSLYSFDY GRFYYGSLYSFDYGRFYYGSLYSFDY ARGRFYYGSLYSFD variable (SEQ ID NO: 72) (SEQ ID NO: 72)(SEQ ID NO: 72) (SEQ ID NO: 72) (SEQ ID NO: 82) region CDR3 Light ChainRASGNIHNYLA RASGNIHNYLA RASGNIHNYLA RASGNIHNYLA HNYLAWY variable(SEQ ID NO: 73) (SEQ ID NO: 73) (SEQ ID NO: 73) (SEQ ID NO: 73)(SEQ ID NO: 83) region CDR1 Light Chain NAKTLAD NAKTLAD NAKTLAD NAKTLADLLVYNAKTLA variable (SEQ ID NO: 74) (SEQ ID NO: 74) (SEQ ID NO: 74)(SEQ ID NO: 74) (SEQ ID NO: 84) region CDR2 Light Chain QHFWTSITQHFWTSIT QHFWTSIT QHFWTSIT QHFWTSI variable (SEQ ID NO: 75)(SEQ ID NO: 75) (SEQ ID NO: 75) (SEQ ID NO: 75) (SEQ ID NO: 85) regionCDR3 47H6 Heavy chain variable region (SEQ ID NO: 131)EVQLQQSGPELVKPGASVKISCKASGYTFTDYYMNWVKQSHGKSLEWIGDFNPNNGGTTYNQKFEGKATLTVDKSSNTAYMDLRSLTSEDSAVYYCARGRFYYGSLYSFDYWGQGTTLTVSS47H6 Light chain variable region (SEQ ID NO: 132)DIQMTQSPASLSASVGETVTITCRASGNIHNYLAWYQQKQGKSPHLLVYNAKTLADGVPSRFSGSGSGTQYSLKINNLQPEDFGSYYCQHFWTSITFGAGTKLDLK

TABLE 4B Anti-ILT2/1LT4 Antibody Hz47H6.v2 Sequences Exemplary ChothiaAbM Kabat Contact Heavy Chain GYTFTDYYMN GYTFTDY GYTFTDYYMN DYYMN TDYYMNvariable (SEQ ID NO: 70) (SEQ ID NO: 76) (SEQ ID NO: 70) (SEQ ID NO: 79)(SEQ ID NO: 80) region CDR1 Heavy Chain DFNPNNAGTTYNQKF NPNNAGDFNPNNAGTT DFNPNNAGTTYNQKFE WIGDFNPNNAGTT variable EG (SEQ ID NO: 119)(SEQ ID NO: 120) G (SEQ ID NO: 121) region CDR2 (SEQ ID NO: 118)(SEQ ID NO: 118) Heavy Chain GRFYYGSLYSFDY GRFYYGSLYSFDY GRFYYGSLYSFDYGRFYYGSLYSFDY ARGRFYYGSLYSFD variable (SEQ ID NO: 72) (SEQ ID NO: 72)(SEQ ID NO: 72) (SEQ ID NO: 72) (SEQ ID NO: 82) region CDR3 Light ChainRASGNIHNYLA RASGNIHNYLA RASGNIHNYLA RASGNIHNYLA HNYLAWY variable(SEQ ID NO: 73) (SEQ ID NO: 73) (SEQ ID NO: 73) (SEQ ID NO: 73)(SEQ ID NO: 83) region CDR1 Light Chain NAKTLAD NAKTLAD NAKTLAD NAKTLADLLIYNAKTLA variable (SEQ ID NO: 74) (SEQ ID NO: 74) (SEQ ID NO: 74)(SEQ ID NO: 74) (SEQ ID NO: 122) region CDR2 Light Chain QHFWTSITQHFWTSIT QHFWTSIT QHFWTSIT QHFWTSI variable (SEQ ID NO: 75)(SEQ ID NO: 75) (SEQ ID NO: 75) (SEQ ID NO: 75) (SEQ ID NO: 85) regionCDR3 Hz47H6.v2 Heavy chain variable region (SEQ ID NO: 133)QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYYMNWVRQAPGQRLEWIGDFNPNNAGTTYNQKFEGRVTITVDKSASTAYMELSSLRSEDTAVYYCARGRFYYGSLYSFDYWGQGTLVTVSSHz47H6.v2 Light chain variable region (SEQ ID NO: 134)DIQMTQSPSSLSASVGDRVTITCRASGNIHNYLAWYQQKPGKAPKLLIYNAKTLADGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQHFWTSITFGPGTKVDIK

TABLE 5 Anti-ILT2/ILT4 Antibody 51A1 Sequences Exemplary Chothia AbMKabat Contact Heavy Chain GFTFNTYAMH GFTFNTY GFTFNTYAMH TYAMH NTYAMHvariable region (SEQ ID NO: 86) (SEQ ID NO: 92) (SEQ ID NO: 86)(SEQ ID NO: 95) (SEQ ID NO: 96) CDR1 Heavy Chain RIRSKSSNYATYYADSRSKSSNYA RIRSKSSNYATY RIRSKSSNYATYYADS WVARIRSKSSNYATY variable regionVKD (SEQ ID NO: 93) (SEQ ID NO: 94) VKD (SEQ ID NO: 97) CDR2(SEQ ID NO: 87) (SEQ ID NO: 87) Heavy Chain DGIYYYGTMYYYAMDGIYYYGTMYYYAM DGIYYYGTMYYYA DGIYYYGTMYYYAMD VRDGIYYYGTMYYYvariable region DY DY MDY Y AMD CDR3 (SEQ ID NO: 88) (SEQ ID NO: 88)(SEQ ID NO: 88) (SEQ ID NO: 88) (SEQ ID NO: 98) Light ChainRASESVDYYGNSFMY RASESVDYYGNSFMY RASESVDYYGNSFM RASESVDYYGNSFMYDYYGNSFMYWY variable region (SEQ ID NO: 89) (SEQ ID NO: 89) Y(SEQ ID NO: 89) (SEQ ID NO: 99) CDR1 (SEQ ID NO: 89) Light Chain FASNLESFASNLES FASNLES FASNLES LLIYFASNLE variable region (SEQ ID NO: 90)(SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 100) CDR2Light Chain QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWvariable region (SEQ ID NO: 91) (SEQ ID NO: 91) (SEQ ID NO: 91)(SEQ ID NO: 91) (SEQ ID NO: 101) CDR351A1 Heavy chain variable region (SEQ ID NO: 135)EVQLVESGGGLVQPKGSLKLSCAASGFTFNTYAMHWVRQAPGKGLEWVARIRSKSSNYATYYADSVKDRFTISRDDSQSMLYLQMNNLKTEDTAMYYCVRDGIYYYGTMYYYAMDYWGQGTSVTVSS51A1 Light chain variable region (SEQ ID NO: 136)NIVLTQSPASLAVSLGQRATISCRASESVDYYGNSFMYWYQQKPGQPPKLLIYFASNLESGVPARFSGSGSRTDFTLTIDPVEAADAASYYCQQNNEDPWTFGGGTKLEIK

TABLE 6A Anti-ILT2/ILT4 Antibody 64A12 Sequences Exemplary Chothia AbMKabat Contact Heavy Chain GFTFNTYAMH GFTFNTY GFTFNTYAMH TYAMH NTYAMHvariable region (SEQ ID NO: 86) (SEQ ID NO: 92) (SEQ ID NO: 86)(SEQ ID NO: 95) (SEQ ID NO: 96) CDR1 Heavy Chain RIRSKSSNYATYYADSRSKSSNYA RIRSKSSNYATY RIRSKSSNYATYYADS WVARIRSKSSNYATY variable regionVKD (SEQ ID NO: 93) (SEQ ID NO: 94) VKD (SEQ ID NO: 97) CDR2(SEQ ID NO: 87) (SEQ ID NO: 87) Heavy Chain DGIYYYDTMYYYAM DGIYYYDTMYYYADGIYYYDTMYYYAM DGIYYYDTMYYYAMD VRDGIYYYDTMYYYA variable region DY MDY DYY MD CDR3 (SEQ ID NO: 102) (SEQ ID NO: 102) (SEQ ID NO: 102)(SEQ ID NO: 102) (SEQ ID NO: 104) Light Chain RASESVDYYGNSFIYRASESVDYYGNSFIY RASESVDYYGNSFIY RASESVDYYGNSFIY DYYGNSFIYWYvariable region (SEQ ID NO: 103) (SEQ ID NO: 103) (SEQ ID NO: 103)(SEQ ID NO: 103) (SEQ ID NO: 105) CDR1 Light Chain FASNLES FASNLESFASNLES FASNLES LLIYFASNLE variable region (SEQ ID NO: 90)(SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 100) CDR2Light Chain QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWvariable region (SEQ ID NO: 91) (SEQ ID NO: 91) (SEQ ID NO: 91)(SEQ ID NO: 91) (SEQ ID NO: 101) CDR364A12 Heavy chain variable region (SEQ ID NO: 137)EVQLVESGGGLVQPKGSLKLSCAASGFTFNTYAMHWVRQAPGKGLEWVARIRSKSSNYATYYADSVKDRFTISRDDSQSMLYLQMNNLKTEDTAMYYCVRDGIYYYDTMYYYAMDYWGQGTSVTVSS64A12 Light chain variable region (SEQ ID NO: 138)NIVLTQSPASLAVSLGQRATISCRASESVDYYGNSFIYWYQQKPGQPPKWYFASNLESGVPARFSGSGSRTDFTLTIDPVEAADAASYYCQQNNEDPWTFGGGTKLEIK

TABLE 6B Anti-ILT2/ILT4 Antibody Hz64A12 Sequences Exemplary Chothia AbMKabat Contact Heavy Chain GFTFNTYAMH GFTFNTY GFTFNTYAMH TYAMH NTYAMHvariable region (SEQ ID NO: 86) (SEQ ID NO: 92) (SEQ ID NO: 86)(SEQ ID NO: 95) (SEQ ID NO: 96) CDR1 Heavy Chain RIRSKSSNYATYYADSRSKSSNYA RIRSKSSNYATY RIRSKSSNYATYYADS WVARIRSKSSNYATY variable regionVKD (SEQ ID NO: 93) (SEQ ID NO: 94) VKD (SEQ ID NO: 97) CDR2(SEQ ID NO: 87) (SEQ ID NO: 87) Heavy Chain DGIYYYDTMYYYAM DGIYYYDTMYYYADGIYYYDTMYYYAM DGIYYYDTMYYYAMD ARDGIYYYDTMYYYA variable region DY MDY DYY MD CDR3 (SEQ ID NO: 102) (SEQ ID NO: 102) (SEQ ID NO: 102)(SEQ ID NO: 102) (SEQ ID NO: 123) Light Chain RASESVDYYGNSFIYRASESVDYYGNSFIY RASESVDYYGNSFIY RASESVDYYGNSFIY DYYGNSFIYWYvariable region (SEQ ID NO: 103) (SEQ ID NO: 103) (SEQ ID NO: 103)(SEQ ID NO: 103) (SEQ ID NO: 105) CDR1 Light Chain FASNLES FASNLESFASNLES FASNLES LLIYFASNLE variable region (SEQ ID NO: 90)(SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 100) CDR2Light Chain QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWvariable region (SEQ ID NO: 91) (SEQ ID NO: 91) (SEQ ID NO: 91)(SEQ ID NO: 91) (SEQ ID NO: 101) CDR3Hz64A12 Heavy chain variable region (SEQ ID NO: 139)EVQLVESGGGLVQPGGSLRLSCAASGFTFNTYAMHWVRQAPGKGLEWVARIRSKSSNYATYYADSVKDRFTISRDDAKNSLYLQMNSLRAEDTAVYYCARDGIYYYDTMYYYAMDYWGQGTLVTVSSHz64A12 Light chain variable region (SEQ ID NO: 140)NIVLTQSPDSLAVSLGERATINCRASESVDYYGNSFIYWYQQKPGQPPKLLIYFASNLESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQQNNEDPWTFGGGTKVEIK

TABLE 7 Anti-ILT2/1LT4 Antibody 73C4 Sequences Exemplary Chothia AbMKabat Contact Heavy Chain GYTFTDYYMN GYTFTDY GYTFTDYYMN DYYMN TDYYMNvariable region (SEQ ID NO: 70) (SEQ ID NO: 76) (SEQ ID NO: 70)(SEQ ID NO: 79) (SEQ ID NO: 80) CDR1 Heavy Chain NVNPNNGGTSYNQK NPNNGGNVNPNNGGTS NVNPNNGGTSYNQKF WIGNVNPNNGGTS variable region FKG(SEQ ID NO: 77) (SEQ ID NO: 108) KG (SEQ ID NO: 109) CDR2(SEQ ID NO: 106) (SEQ ID NO: 106) Heavy Chain REIYFYGTIYYYAMDREIYFYGTIYYYAM REIYFYGTIYYYAM REIYFYGTIYYYAMDY ARREIYFYGTIYYYAvariable region Y DY DY MD CDR3 (SEQ ID NO: 107) (SEQ ID NO: 107)(SEQ ID NO: 107) (SEQ ID NO: 107) (SEQ ID NO: 110) Light ChainRASESVDYYGNSFM RASESVDYYGNSF RASESVDYYGNSF RASESVDYYGNSFMY DYYGNSFMYWYvariable region Y MY MY (SEQ ID NO: 89) (SEQ ID NO: 99) CDR1(SEQ ID NO: 89) (SEQ ID NO: 89) (SEQ ID NO: 89) Light Chain FASNLESFASNLES FASNLES FASNLES LLIYFASNLE variable region (SEQ ID NO: 90)(SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 100) CDR2Light Chain QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWvariable region (SEQ ID NO: 91) (SEQ ID NO: 91) (SEQ ID NO: 91)(SEQ ID NO: 91) (SEQ ID NO: 101) CDR373C4 Heavy chain variable region (SEQ ID NO: 141)AVQLQQSGPELVKPGASVKISCKASGYTFTDYYMNWVKQSHGKSLEWIGNVNPNNGGTSYNQKFKGKATLTVDKSSSTAYMELRSLTSEDSAVYYCARREIYFYGTIYYYAMDYWGQGTSVTVSS73C4 Light chain variable region (SEQ ID NO: 142)DIVLTQSPASLAVSLGQRATISCRASESVDYYGNSFMYWYQQKPGRPPNLLIYFASNLESGVPARFSGSGSRTDFTLTIDPVEADDAATYYCQQNNEDPWTFGGGTKLEIK

TABLE 8A Anti-ILT2/1LT4 Antibody 73D1 Sequences Exemplary Chothia AbMKabat Contact Heavy Chain GYTFTDYYIN GYTFTDY GYTFTDYYIN DYYIN TDYYINvariable (SEQ ID NO: 111) (SEQ ID NO: 76) (SEQ ID NO: 111)(SEQ ID NO: 115) (SEQ ID NO: 116) region CDR1 Heavy ChainNVNPNDGGTTYNQKF NPNDGG NVNPNDGGTT NVNPNDGGTTYNQKF WIGNVNPNDGGTT variableKG (SEQ ID NO: 113) (SEQ ID NO: 114) KG (SEQ ID NO: 117) region CDR2(SEQ ID NO: 112) (SEQ ID NO: 112) Heavy Chain REIYFYGTIYYYAMDREIYFYGTIYYYAM REIYFYGTIYYYAM REIYFYGTIYYYAMDY ARREIYFYGTIYYY variable YDY DY (SEQ ID NO: 107) AMD region CDR3 (SEQ ID NO: 107) (SEQ ID NO: 107)(SEQ ID NO: 107) (SEQ ID NO: 110) Light Chain RASESVDYYGNSFMYRASESVDYYGNSF RASESVDYYGNSF RASESVDYYGNSFMY DYYGNSFMYWY variable(SEQ ID NO: 89) MY MY (SEQ ID NO: 89) (SEQ ID NO: 99) region CDR1(SEQ ID NO: 89) (SEQ ID NO: 89) Light Chain FASNLES FASNLES FASNLESFASNLES LLIYFASNLE variable (SEQ ID NO: 90) (SEQ ID NO: 90)(SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 100) region CDR2 Light ChainQQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPW variable(SEQ ID NO: 91) (SEQ ID NO: 91) (SEQ ID NO: 91) (SEQ ID NO: 91)(SEQ ID NO: 101) region CDR373D1 Heavy chain variable region (SEQ ID NO: 143)AVQLQQSGPELVKPGASVKISCKASGYTFTDYYINWVKQSHGKSLQWIGNVNPNDGGTTYNQKFKGKATLTVDKSSSTAYMELRSLTSEDSAVYYCARREIYFYGTIYYYAMDYWGQGTSVTVSS73D1 Light chain variable region (SEQ ID NO: 142)DIVLTQSPASLAVSLGQRATISCRASESVDYYGNSFMYWYQQKPGRPPNLLIYFASNLESGVPARFSGSGSRTDFTLTIDPVEADDAATYYCQQNNEDPWTFGGGTKLEIK

TABLE 8B Anti-ILT2/1LT4 Antibody Hz73D1.v1 Sequences Exemplary ChothiaAbM Kabat Contact Heavy Chain GYTFTDYYIN GYTFTDY GYTFTDYYIN DYYIN TDYYINvariable (SEQ ID NO: 111) (SEQ ID NO: 76) (SEQ ID NO: 111)(SEQ ID NO: 115) (SEQ ID NO: 116) region CDR1 Heavy ChainNVNPNDGGTTYNQKF NPNDGG NVNPNDGGTT NVNPNDGGTTYNQKF WMGNVNPNDGGTT variableKG (SEQ ID NO: 113) (SEQ ID NO: 114) KG (SEQ ID NO: 124) region CDR2(SEQ ID NO: 112) (SEQ ID NO: 112) Heavy Chain REIYFYGTIYYYAMDREIYFYGTIYYYAM REIYFYGTIYYYAM REIYFYGTIYYYAMDY ARREIYFYGTIYYY variable YDY DY (SEQ ID NO: 107) (SEQ ID NO: 110) region CDR3 (SEQ ID NO: 107)(SEQ ID NO: 107) (SEQ ID NO: 107) Light Chain RASESVDYYGNSFMYRASESVDYYGNSF RASESVDYYGNSF RASESVDYYGNSFMY DYYGNSFMYWY variable(SEQ ID NO: 89) MY MY (SEQ ID NO: 89) (SEQ ID NO: 99) region CDR1(SEQ ID NO: 89) (SEQ ID NO: 89) Light Chain FASNLES FASNLES FASNLESFASNLES LLIYFASNLE variable (SEQ ID NO: 90) (SEQ ID NO: 90)(SEQ ID NO: 90) (SEQ ID NO: 90) (SEQ ID NO: 100) region CDR2 Light ChainQQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPWT QQNNEDPW variable(SEQ ID NO: 91) (SEQ ID NO: 91) (SEQ ID NO: 91) (SEQ ID NO: 91)(SEQ ID NO: 101) region CDR3Hz73D1.v1 Heavy chain variable region (SEQ ID NO: 144)QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYYINWVRQAPGQGLEWMGNVNPNDGGTTYNQKFKGRVTMTTDTSTSTAYMELRSLRSDDTAVYYCARREIYFYGTIYYYAMDYWGQGTLVTVSSHz73D1.v1 Light chain variable region (SEQ ID NO: 145)DIQLTQSPSFLSASVGDRVTITCRASESVDYYGNSFMYWYQQKPGKAPKLLIYFASNLESGVPSRFSGSGSGTEFTLTISSLQPEDFATYYCQQNNEDPWTFGGGTKVEIK

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) comprises a heavychain variable region CDR1, CDR2, and CDR3 and/or a light chain variableregion CDR1, CDR2, and CDR3 from an antibody described herein. In someembodiments, an ILT-binding agent comprises a heavy chain variableregion CDR1, CDR2, and CDR3 and a light chain variable region CDR1,CDR2, and CDR3 from an antibody described herein. In some embodiments,an ILT-binding agent comprises: (a) a heavy chain variable regioncomprising a heavy chain variable region CDR1, CDR2, and CDR3; and (b) alight chain variable region comprising a light chain variable regionCDR1, CDR2, and CDR3 from an antibody described herein.

In some embodiments, an ILT-binding agent (e.g., an anti-ILT2 antibody,an anti-ILT4 antibody, or an anti-ILT2/ILT4 antibody) comprises one ormore (e.g., 1, 2, 3, 4, etc.) amino acid substitutions in a CDR of anantibody described herein. In some embodiments, the amino acidsubstitutions are conservative substitutions. In some embodiments, a CDRcomprises one amino acid substitution. In some embodiments, a CDRcomprises two amino acid substitutions. In some embodiments, a CDRcomprises three amino acid substitutions. In some embodiments, a CDRcomprises four amino acid substitutions. In some embodiments, the CDR isa heavy chain variable region CDR1. In some embodiments, the CDR is aheavy chain variable region CDR2. In some embodiment, the CDR is a heavychain variable region CDR3. In some embodiments, the CDR is a lightchain variable region CDR1. In some embodiments, the CDR is a lightchain variable region CDR2. In some embodiments, the CDR is a lightchain variable region CDR3. In some embodiments, the substitutions aremade as part of a humanization process. In some embodiments, thesubstitutions are made as part of a germline humanization process. Insome embodiments, the substitutions are made as part of an affinitymaturation process. In some embodiments, the substitutions are made aspart of an optimization process.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) comprises one ormore heavy chain variable region CDRs or light chain variable regionCDRs that have been modified to reduce deamidation within the CDRsequence. Deamidation is a chemical reaction in which an amidefunctional group in the side chain of the amino acids asparagine (Asn orN) or glutamine (Gln or Q) is removed or converted to another functionalgroup. Generally, asparagine is converted to aspartic acid orisoaspartic acid and glutamine is converted to glutamic acid orpolyglutamic acid. In some situations, deamidation may change thestructure, function, and/or stability of a polypeptide, potentiallyresulting in decreased biological activity. In some embodiments, theheavy chain variable region CDR1, CDR2, and/or CDR3 of an antibodydescribed herein is modified to reduce deamidation. In some embodiments,the light chain variable region CDR1, CDR2, and/or CDR3 of an antibodydescribed herein is modified to reduce deamidation.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) comprises one ormore heavy chain variable region CDRs or light chain variable regionCDRs that have been modified to reduce isomerization. Isomerization is achemical process by which a compound is transformed into any of itsisomeric forms, i.e., forms with the same chemical composition but withdifferent structure or configuration and, potentially with differentphysical and chemical properties. Studies have shown that asparatate(Asp or D) isomerization within a CDR can impact antibody binding and/orstability. In some embodiments, the heavy chain variable region CDR1,CDR2, and/or CDR3 of an antibody described herein is modified to reduceisomerization. In some embodiments, the light chain variable regionCDR1, CDR2, and/or CDR3 is modified to reduce isomerization.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4 binding agent) comprises one ormore heavy chain variable region CDRs or light chain variable regionCDRs that have been modified to reduce oxidation. Oxidation is achemical process by which an oxygen is added to an atom, for example,methionine is converted to methionine sulfoxide by addition of an oxygento the sulfur atom. Oxidation of one or more amino acids can potentiallyaffect the physical and chemical properties of a protein. Studies haveshown that oxidation of methionine (Met or M) within a CDR has thepotential to impact antibody binding and/or stability. In someembodiments, the heavy chain variable region CDR1, CDR2, and/or CDR3 ofan antibody described herein is modified to reduce oxidation (e.g.,methionine oxidation). In some embodiments, the light chain variableregion CDR1, CDR2, and/or CDR3 of an antibody described herein ismodified to reduce oxidation (e.g., methionine oxidation).

In some embodiments, an ILT2-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 and/or a light chain variableregion CDR1, CDR2, and CDR3 from antibody 27F9, a humanized versionthereof, or variants thereof. In some embodiments, an ILT2-binding agentcomprises a heavy chain variable region comprising a heavy chainvariable region CDR1, a heavy chain variable region CDR2, and a heavychain variable region CDR3 from antibody 27F9. In other embodiments, anILT2-binding agent comprises a light chain variable region comprising alight chain variable region CDR1, a light chain variable region CDR2,and a light chain variable region CDR3 from antibody 27F9 In someembodiments, an ILT2-binding agent comprises: (a) a heavy chain variableregion comprising a heavy chain variable region CDR1, a heavy chainvariable region CDR2, a heavy chain variable region CDR3; and (b) alight chain variable region comprising a light chain variable regionCDR1, a light chain variable region CDR2, and a light chain variableregion CDR3 from antibody 27F9. In some embodiments, an ILT2-bindingagent is a humanized version of antibody 27F9. In some embodiments, anILT2-binding agent is a variant of antibody 27F9 or humanized 27F9.

In some embodiments, an ILT2-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GFSLTNYGVS (SEQ ID NO:22), a heavy chainvariable region CDR2 comprising the amino acid sequence IIWGDGSTNYHSALIS(SEQ ID NO:23), and a heavy chain variable region CDR3 comprising theamino acid sequence PNWDTYAMDF (SEQ ID NO:24), and a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASQDISNFLN (SEQ ID NO:25), a light chainvariable region CDR2 comprising the amino acid sequence CTSKLHS (SEQ IDNO:26), and a light chain variable region CDR3 comprising the amino acidsequence QQGNTLPPT (SEQ ID NO:27); (b) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence GFSLTNY (SEQ ID NO:28), a heavy chain variable region CDR2comprising the amino acid sequence WGDGS (SEQ ID NO:29), and a heavychain variable region CDR3 comprising the amino acid sequence PNWDTYAMDF(SEQ ID NO:24), and a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASQDISNFLN (SEQ ID NO:25), a light chain variable region CDR2comprising the amino acid sequence CTSKLHS (SEQ ID NO:26), and a lightchain variable region CDR3 comprising the amino acid sequence QQGNTLPPT(SEQ ID NO:27); (c) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence GFSLTNYGVS(SEQ ID NO:22), a heavy chain variable region CDR2 comprising the aminoacid sequence IIWGDGSTN (SEQ ID NO:30), and a heavy chain variableregion CDR3 comprising the amino acid sequence PNWDTYAMDF (SEQ IDNO:24), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASQDISNFLN (SEQID NO:25), a light chain variable region CDR2 comprising the amino acidsequence CTSKLHS (SEQ ID NO:26), and a light chain variable region CDR3comprising the amino acid sequence QQGNTLPPT (SEQ ID NO:27); (d) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence NYGVS (SEQ ID NO:31), a heavy chainvariable region CDR2 comprising the amino acid sequence IIWGDGSTNYHSALIS(SEQ ID NO:23), and a heavy chain variable region CDR3 comprising theamino acid sequence PNWDTYAMDF (SEQ ID NO:24), and a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASQDISNFLN (SEQ ID NO:25), a light chainvariable region CDR2 comprising the amino acid sequence CTSKLHS (SEQ IDNO:26), and a light chain variable region CDR3 comprising the amino acidsequence QQGNTLPPT (SEQ ID NO:27); or (e) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence TNYGVS (SEQ ID NO:32), a heavy chain variable region CDR2comprising the amino acid sequence WLGIIWGDGSTN (SEQ ID NO:33), and aheavy chain variable region CDR3 comprising the amino acid sequenceAKPNWDTYAMD (SEQ ID NO:34), and a light chain variable region comprisinga light chain variable region CDR1 comprising the amino acid sequenceSNFLNWY (SEQ ID NO:35), a light chain variable region CDR2 comprisingthe amino acid sequence LLIYCTSKLH (SEQ ID NO:36), and a light chainvariable region CDR3 comprising the amino acid sequence QQGNTLPP (SEQ IDNO:37).

In some embodiments, an ILT2-binding agent comprises: (a) a heavy chainvariable region comprising heavy chain variable region CDR1 comprisingthe amino acid sequence GFSLTNYGVS (SEQ ID NO:22), a heavy chainvariable region CDR2 comprising the amino acid sequence IIWGDGSTNYHSALIS(SEQ ID NO:23), and a heavy chain variable region CDR3 comprising theamino acid sequence PNWDTYAMDF (SEQ ID NO:24), and/or (b) a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASQDISNFLN (SEQ ID NO:25), a light chainvariable region CDR2 comprising the amino acid sequence CTSKLHS (SEQ IDNO:26), and a light chain variable region CDR3 comprising the amino acidsequence QQGNTLPPT (SEQ ID NO:27). In some embodiments, the ILT2-bindingagent comprises a heavy chain variable region comprising heavy chainvariable region CDR1 comprising the amino acid sequence GFSLTNYGVS (SEQID NO:22), a heavy chain variable region CDR2 comprising the amino acidsequence IIWGDGSTNYHSALIS (SEQ ID NO:23), and a heavy chain variableregion CDR3 comprising the amino acid sequence PNWDTYAMDF (SEQ IDNO:24). In some embodiments, the ILT2-binding agent comprises a lightchain variable region comprising a light chain variable region CDR1comprising the amino acid sequence RASQDISNFLN (SEQ ID NO:25), a lightchain variable region CDR2 comprising the amino acid sequence CTSKLHS(SEQ ID NO:26), and a light chain variable region CDR3 comprising theamino acid sequence QQGNTLPPT (SEQ ID NO:27). In some embodiments, theILT2-binding agent comprises: (a) a heavy chain variable regioncomprising heavy chain variable region CDR1 comprising the amino acidsequence GFSLTNYGVS (SEQ ID NO:22), a heavy chain variable region CDR2comprising the amino acid sequence IIWGDGSTNYHSALIS (SEQ ID NO:23), anda heavy chain variable region CDR3 comprising the amino acid sequencePNWDTYAMDF (SEQ ID NO:24), and (b) a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence RASQDISNFLN (SEQ ID NO:25), a light chain variable region CDR2comprising the amino acid sequence CTSKLHS (SEQ ID NO:26), and a lightchain variable region CDR3 comprising the amino acid sequence QQGNTLPPT(SEQ ID NO:27).

In some embodiments, an anti-ILT2 binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody 27F9 and which has atleast 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:125 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody 27F9 and which has at least 75%, at least80%, at least 85%, at least 90%, at least 95%, at least 96%, at least97%, at least 98%, at least 99%, or 100% identity to the sequence of SEQID NO:126.

In some embodiments, an ILT2-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:125. In some embodiments, an ILT2-binding agent comprises a lightchain variable region having at least 80%, at least 85%, at least 90%,at least 95%, at least 97%, or at least 99% identity to the sequence ofSEQ ID NO:126. In some embodiments, an ILT2-binding agent comprises aheavy chain variable region comprising an amino acid sequence of SEQ IDNO:125. In some embodiments, an ILT2-binding agent comprises a lightchain variable region comprising an amino acid sequence of SEQ IDNO:126.

In some embodiments, an ILT2-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:125and a light chain variable region having at least 80% sequence identityto SEQ ID NO:126. In some embodiments, an ILT2-binding agent comprises aheavy chain variable region having at least 90% sequence identity to SEQID NO:125 and a light chain variable region having at least 90% sequenceidentity to SEQ ID NO:126. In some embodiments, an ILT2-binding agentcomprises a heavy chain variable region having at least 95% sequenceidentity to SEQ ID NO:125 and a light chain variable region having atleast 95% sequence identity to SEQ ID NO:126. In some embodiments, anILT2-binding agent comprises a heavy chain variable region comprising anamino acid sequence of SEQ ID NO:125 and a light chain variable regioncomprising an amino acid sequence of SEQ ID NO:126.

In some embodiments, an ILT4-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 and/or a light chain variableregion CDR1, CDR2, and CDR3 from antibody 47C8, a humanized versionthereof, or variants thereof. In some embodiments, an ILT4-binding agentcomprises a heavy chain variable region comprising a heavy chainvariable region CDR1, a heavy chain variable region CDR2, and a heavychain variable region CDR3 from antibody 47C8. In other embodiments, anILT4-binding agent comprises a light chain variable region comprising alight chain variable region CDR1, a light chain variable region CDR2,and a light chain variable region CDR3 from antibody 47C8 In someembodiments, an ILT4-binding agent comprises: (a) a heavy chain variableregion comprising a heavy chain variable region CDR1, a heavy chainvariable region CDR2, a heavy chain variable region CDR3; and (b) alight chain variable region comprising a light chain variable regionCDR1, a light chain variable region CDR2, and a light chain variableregion CDR3 from antibody 47C8. In some embodiments, an ILT4-bindingagent is a humanized version of antibody 47C8. In some embodiments, anILT4-binding agent is a variant of antibody 47C8 or humanized 47C8.

In some embodiments, an ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYSFTGYYMH (SEQ ID NO:38), a heavy chainvariable region CDR2 comprising the amino acid sequenceRVYPNNGDTSYNQKFKV (SEQ ID NO:39), and a heavy chain variable region CDR3comprising the amino acid sequence GATVVESLFAY (SEQ ID NO:40), and alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASESVDNYGNNFLH (SEQ ID NO:41),a light chain variable region CDR2 comprising the amino acid sequenceRTSNLES (SEQ ID NO:42), and a light chain variable region CDR3comprising the amino acid sequence QQSNEDPYT (SEQ ID NO:43); (b) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYSFTGY (SEQ ID NO:44), a heavy chainvariable region CDR2 comprising the amino acid sequence YPNNGD (SEQ IDNO:45), and a heavy chain variable region CDR3 comprising the amino acidsequence GATVVESLFAY (SEQ ID NO:40), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence RASESVDNYGNNFLH (SEQ ID NO:41), a light chain variable regionCDR2 comprising the amino acid sequence RTSNLES (SEQ ID NO:42), and alight chain variable region CDR3 comprising the amino acid sequenceQQSNEDPYT (SEQ ID NO:43); (c) a heavy chain variable region comprising aheavy chain variable region CDR1 comprising the amino acid sequenceGYSFTGYYMH (SEQ ID NO:38), a heavy chain variable region CDR2 comprisingthe amino acid sequence RVYPNNGDTS (SEQ ID NO:46), and a heavy chainvariable region CDR3 comprising the amino acid sequence GATVVESLFAY (SEQID NO:40), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDNYGNNFLH(SEQ ID NO:41), a light chain variable region CDR2 comprising the aminoacid sequence RTSNLES (SEQ ID NO:42), and a light chain variable regionCDR3 comprising the amino acid sequence QQSNEDPYT (SEQ ID NO:43); (d) aheavy chain variable region comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GYYMH (SEQ ID NO:47), a heavychain variable region CDR2 comprising the amino acid sequenceRVYPNNGDTSYNQKFKV (SEQ ID NO:39), and a heavy chain variable region CDR3comprising the amino acid sequence GATVVESLFAY (SEQ ID NO:40), and alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASESVDNYGNNFLH (SEQ ID NO:41),a light chain variable region CDR2 comprising the amino acid sequenceRTSNLES (SEQ ID NO:42), and a light chain variable region CDR3comprising the amino acid sequence QQSNEDPYT (SEQ ID NO:43); or (e) aheavy chain variable region comprising a heavy chain variable regionCDR1 comprising the amino acid sequence TGYYMH (SEQ ID NO:48), a heavychain variable region CDR2 comprising the amino acid sequenceWIGRVYPNNGDTS (SEQ ID NO:49), and a heavy chain variable region CDR3comprising the amino acid sequence ARGATVVESLFA (SEQ ID NO:50), and alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence DNYGNNFLHWY (SEQ ID NO:51), alight chain variable region CDR2 comprising the amino acid sequenceLLIYRTSNLE (SEQ ID NO:52), and a light chain variable region CDR3comprising the amino acid sequence QQSNEDPY (SEQ ID NO:53).

In some embodiments, an ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYSFTGYYMH (SEQ ID NO:38), a heavy chainvariable region CDR2 comprising the amino acid sequenceRVYPNNGDTSYNQKFKV (SEQ ID NO:39), and a heavy chain variable region CDR3comprising the amino acid sequence GATVVESLFAY (SEQ ID NO:40), and/or(b) a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence RASESVDNYGNNFLH (SEQ IDNO:41), a light chain variable region CDR2 comprising the amino acidsequence RTSNLES (SEQ ID NO:42), and a light chain variable region CDR3comprising the amino acid sequence QQSNEDPYT (SEQ ID NO:43). In someembodiments, the ILT4-binding agent comprises a heavy chain variableregion comprising a heavy chain variable region CDR1 comprising theamino acid sequence GYSFTGYYMH (SEQ ID NO:38), a heavy chain variableregion CDR2 comprising the amino acid sequence RVYPNNGDTSYNQKFKV (SEQ IDNO:39), and a heavy chain variable region CDR3 comprising the amino acidsequence GATVVESLFAY (SEQ ID NO:40). In some embodiments, theILT4-binding agent comprises a light chain variable region comprising alight chain variable region CDR1 comprising the amino acid sequenceRASESVDNYGNNFLH (SEQ ID NO:41), a light chain variable region CDR2comprising the amino acid sequence RTSNLES (SEQ ID NO:42), and a lightchain variable region CDR3 comprising the amino acid sequence QQSNEDPYT(SEQ ID NO:43). In some embodiments, the ILT4-binding agent comprises:(a) a heavy chain variable region comprising a heavy chain variableregion CDR1 comprising the amino acid sequence GYSFTGYYMH (SEQ IDNO:38), a heavy chain variable region CDR2 comprising the amino acidsequence RVYPNNGDTSYNQKFKV (SEQ ID NO:39), and a heavy chain variableregion CDR3 comprising the amino acid sequence GATVVESLFAY (SEQ IDNO:40), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDNYGNNFLH(SEQ ID NO:41), a light chain variable region CDR2 comprising the aminoacid sequence RTSNLES (SEQ ID NO:42), and a light chain variable regionCDR3 comprising the amino acid sequence QQSNEDPYT (SEQ ID NO:43).

In some embodiments, an anti-ILT4 binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody 47C8 and which has atleast 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:127 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody 47C8 and which has at least 75%, at least80%, at least 85%, at least 90%, at least 95%, at least 96%, at least97%, at least 98%, at least 99%, or 100% identity to the sequence of SEQID NO:128.

In some embodiments, an ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:127. In some embodiments, an ILT4-binding agent comprises a lightchain variable region having at least 80%, at least 85%, at least 90%,at least 95%, at least 97%, or at least 99% identity to the sequence ofSEQ ID NO:128. In some embodiments, an ILT4-binding agent comprises aheavy chain variable region comprising an amino acid sequence of SEQ IDNO:127. In some embodiments, an ILT4-binding agent comprises a lightchain variable region comprising an amino acid sequence of SEQ IDNO:128.

In some embodiments, an ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:127and a light chain variable region having at least 80% sequence identityto SEQ ID NO:128. In some embodiments, an ILT4-binding agent comprises aheavy chain variable region having at least 90% sequence identity to SEQID NO:127 and a light chain variable region having at least 90% sequenceidentity to SEQ ID NO:128. In some embodiments, an ILT4-binding agentcomprises a heavy chain variable region having at least 95% sequenceidentity to SEQ ID NO:127 and a light chain variable region having atleast 95% sequence identity to SEQ ID NO:128. In some embodiments, anILT4-binding agent comprises a heavy chain variable region comprising anamino acid sequence of SEQ ID NO:127 and a light chain variable regioncomprising an amino acid sequence of SEQ ID NO:128.

In some embodiments, an ILT4-binding agent comprises a heavy chainvariable region CDR1, CDR2, and CDR3 and/or a light chain variableregion CDR1, CDR2, and CDR3 from antibody 48A5, a humanized versionthereof, or variants thereof. In some embodiments, an ILT4-binding agentcomprises a heavy chain variable region comprising a heavy chainvariable region CDR1, a heavy chain variable region CDR2, and a heavychain variable region CDR3 from antibody 48A5. In other embodiments, anILT4-binding agent comprises a light chain variable region comprising alight chain variable region CDR1, a light chain variable region CDR2,and a light chain variable region CDR3 from antibody 48A5 In someembodiments, an ILT4-binding agent comprises: (a) a heavy chain variableregion comprising a heavy chain variable region CDR1, a heavy chainvariable region CDR2, a heavy chain variable region CDR3; and (b) alight chain variable region comprising a light chain variable regionCDR1, a light chain variable region CDR2, and a light chain variableregion CDR3 from antibody 48A5. In some embodiments, an ILT4-bindingagent is a humanized version of antibody 48A5. In some embodiments, anILT4-binding agent is a variant of antibody 48A5 or humanized 48A5.

In some embodiments, an ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYTFTNYGMN (SEQ ID NO:54), a heavy chainvariable region CDR2 comprising the amino acid sequenceWINTYIGEPIYADDFKG (SEQ ID NO:55), and a heavy chain variable region CDR3comprising the amino acid sequence RSDYDGYAMDY (SEQ ID NO:56), and alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence KSSQSLLYSGNQKNYLA (SEQ IDNO:57), a light chain variable region CDR2 comprising the amino acidsequence WASTRES (SEQ ID NO:58), and a light chain variable region CDR3comprising the amino acid sequence QQHDSYPT (SEQ ID NO:59); (b) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTNY (SEQ ID NO:60), a heavy chainvariable region CDR2 comprising the amino acid sequence NTYIGE (SEQ IDNO:61), and a heavy chain variable region CDR3 comprising the amino acidsequence RSDYDGYAMDY (SEQ ID NO:56), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence KSSQSLLYSGNQKNYLA (SEQ ID NO:57), a light chain variable regionCDR2 comprising the amino acid sequence WASTRES (SEQ ID NO:58), and alight chain variable region CDR3 comprising the amino acid sequenceQQHDSYPT (SEQ ID NO:59); (c) a heavy chain variable region comprising aheavy chain variable region CDR1 comprising the amino acid sequenceGYTFTNYGMN (SEQ ID NO:54), a heavy chain variable region CDR2 comprisingthe amino acid sequence WINTYIGEPI (SEQ ID NO:62), and a heavy chainvariable region CDR3 comprising the amino acid sequence RSDYDGYAMDY (SEQID NO:56), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequenceKSSQSLLYSGNQKNYLA (SEQ ID NO:57), a light chain variable region CDR2comprising the amino acid sequence WASTRES (SEQ ID NO:58), and a lightchain variable region CDR3 comprising the amino acid sequence QQHDSYPT(SEQ ID NO:59); (d) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence NYGMN (SEQID NO:63), a heavy chain variable region CDR2 comprising the amino acidsequence WINTYIGEPIYADDFKG (SEQ ID NO:55), and a heavy chain variableregion CDR3 comprising the amino acid sequence RSDYDGYAMDY (SEQ IDNO:56), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequenceKSSQSLLYSGNQKNYLA (SEQ ID NO:57), a light chain variable region CDR2comprising the amino acid sequence WASTRES (SEQ ID NO:58), and a lightchain variable region CDR3 comprising the amino acid sequence QQHDSYPT(SEQ ID NO:59); or (e) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence TNYGMN(SEQ ID NO:64), a heavy chain variable region CDR2 comprising the aminoacid sequence WMGWINTYIGEPI (SEQ ID NO:65), and a heavy chain variableregion CDR3 comprising the amino acid sequence ARRSDYDGYAMD (SEQ IDNO:66), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence LYSGNQKNYLAWY(SEQ ID NO:67), a light chain variable region CDR2 comprising the aminoacid sequence LLIYWASTRE (SEQ ID NO:68), and a light chain variableregion CDR3 comprising the amino acid sequence QQHDSYP (SEQ ID NO:69).

In some embodiments, an ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYTFTNYGMN (SEQ ID NO:54), a heavy chainvariable region CDR2 comprising the amino acid sequenceWINTYIGEPIYADDFKG (SEQ ID NO:55), and a heavy chain variable region CDR3comprising the amino acid sequence RSDYDGYAMDY (SEQ ID NO:56), and/or(b) a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence KSSQSLLYSGNQKNYLA (SEQ IDNO:57), a light chain variable region CDR2 comprising the amino acidsequence WASTRES (SEQ ID NO:58), and a light chain variable region CDR3comprising the amino acid sequence QQHDSYPT (SEQ ID NO:59). In someembodiments, the ILT4-binding agent comprises a heavy chain variableregion comprising a heavy chain variable region CDR1 comprising theamino acid sequence GYTFTNYGMN (SEQ ID NO:54), a heavy chain variableregion CDR2 comprising the amino acid sequence WINTYIGEPIYADDFKG (SEQ IDNO:55), and a heavy chain variable region CDR3 comprising the amino acidsequence RSDYDGYAMDY (SEQ ID NO:56). In some embodiments, theILT4-binding agent comprises a light chain variable region comprising alight chain variable region CDR1 comprising the amino acid sequenceKSSQSLLYSGNQKNYLA (SEQ ID NO:57), a light chain variable region CDR2comprising the amino acid sequence WASTRES (SEQ ID NO:58), and a lightchain variable region CDR3 comprising the amino acid sequence QQHDSYPT(SEQ ID NO:59). In some embodiments, the ILT4-binding agent comprises:(a) a heavy chain variable region comprising a heavy chain variableregion CDR1 comprising the amino acid sequence GYTFTNYGMN (SEQ IDNO:54), a heavy chain variable region CDR2 comprising the amino acidsequence WINTYIGEPIYADDFKG (SEQ ID NO:55), and a heavy chain variableregion CDR3 comprising the amino acid sequence RSDYDGYAMDY (SEQ IDNO:56), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequenceKSSQSLLYSGNQKNYLA (SEQ ID NO:57), a light chain variable region CDR2comprising the amino acid sequence WASTRES (SEQ ID NO:58), and a lightchain variable region CDR3 comprising the amino acid sequence QQHDSYPT(SEQ ID NO:59).

In some embodiments, an anti-ILT4 binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody 48A5 and which has atleast 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:129 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody 48A5 and which has at least 75%, at least80%, at least 85%, at least 90%, at least 95%, at least 96%, at least97%, at least 98%, at least 99%, or 100% identity to the sequence of SEQID NO:130.

In some embodiments, an ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:129. In some embodiments, an ILT4-binding agent comprises a lightchain variable region having at least 80%, at least 85%, at least 90%,at least 95%, at least 97%, or at least 99% identity to the sequence ofSEQ ID NO:130. In some embodiments, an ILT4-binding agent comprises aheavy chain variable region comprising an amino acid sequence of SEQ IDNO:129. In some embodiments, an ILT4-binding agent comprises a lightchain variable region comprising an amino acid sequence of SEQ IDNO:130.

In some embodiments, an ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:129and a light chain variable region having at least 80% sequence identityto SEQ ID NO:130. In some embodiments, an ILT4-binding agent comprises aheavy chain variable region having at least 90% sequence identity to SEQID NO:129 and a light chain variable region having at least 90% sequenceidentity to SEQ ID NO:130. In some embodiments, an ILT4-binding agentcomprises a heavy chain variable region having at least 95% sequenceidentity to SEQ ID NO:129 and a light chain variable region having atleast 95% sequence identity to SEQ ID NO:130. In some embodiments, anILT4-binding agent comprises a heavy chain variable region comprising anamino acid sequence of SEQ ID NO:129 and a light chain variable regioncomprising an amino acid sequence of SEQ ID NO:130.

In some embodiments, an ILT2/ILT4-binding agent (e.g., a dual binder)comprises a heavy chain variable region CDR1, CDR2, and CDR3 and/or alight chain variable region CDR1, CDR2, and CDR3 from antibody 47H6, ahumanized version thereof (e.g., Hz47H6.v2), or variants thereof. Insome embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising a heavy chain variable region CDR1, a heavychain variable region CDR2, and a heavy chain variable region CDR3 fromantibody 47H6 or antibody Hz47H6.v2. In other embodiments, anILT2/ILT4-binding agent comprises a light chain variable regioncomprising a light chain variable region CDR1, a light chain variableregion CDR2, and a light chain variable region CDR3 from antibody 47H6or antibody Hz47H6.v2. In some embodiments, an ILT2/ILT4-binding agentcomprises: (a) a heavy chain variable region comprising a heavy chainvariable region CDR1, a heavy chain variable region CDR2, a heavy chainvariable region CDR3; and (b) a light chain variable region comprising alight chain variable region CDR1, a light chain variable region CDR2,and a light chain variable region CDR3 from antibody 47H6. In someembodiments, an ILT2/ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1, a heavychain variable region CDR2, a heavy chain variable region CDR3; and (b)a light chain variable region comprising a light chain variable regionCDR1, a light chain variable region CDR2, and a light chain variableregion CDR3 from antibody Hz47H6.v2. In some embodiments, anILT2/ILT4-binding agent is a humanized version of antibody 47H6. In someembodiments, an ILT2/ILT4-binding agent is a variant of antibody 47H6.In some embodiments, an ILT2/ILT4-binding agent is a variant of antibodyHz47H6.v2.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavychain variable region CDR2 comprising the amino acid sequenceDFNPNNGGTTYNQKFEG (SEQ ID NO:71) or DFNPNNAGTTYNQKFEG (SEQ ID NO:118),and a heavy chain variable region CDR3 comprising the amino acidsequence GRFYYGSLYSFDY (SEQ ID NO:72), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence RASGNIHNYLA (SEQ ID NO:73), a light chain variable region CDR2comprising the amino acid sequence NAKTLAD (SEQ ID NO:74), and a lightchain variable region CDR3 comprising the amino acid sequence QHFWTSIT(SEQ ID NO:75); (b) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence GYTFTDY(SEQ ID NO:76), a heavy chain variable region CDR2 comprising the aminoacid sequence NPNNGG (SEQ ID NO:77) or the amino acid sequence NPNNAG(SEQ ID NO:119), and a heavy chain variable region CDR3 comprising theamino acid sequence GRFYYGSLYSFDY (SEQ ID NO:72), and a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASGNIHNYLA (SEQ ID NO:73), a light chainvariable region CDR2 comprising the amino acid sequence NAKTLAD (SEQ IDNO:74), and a light chain variable region CDR3 comprising the amino acidsequence QHFWTSIT (SEQ ID NO:75); (c) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence GYTFTDYYMN (SEQ ID NO:70), a heavy chain variable region CDR2comprising the amino acid sequence DFNPNNGGTT (SEQ ID NO:78) or theamino acid sequence DFNPNNAGTT (SEQ ID NO:120), and a heavy chainvariable region CDR3 comprising the amino acid sequence GRFYYGSLYSFDY(SEQ ID NO:72), and a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASGNIHNYLA (SEQ ID NO:73), a light chain variable region CDR2comprising the amino acid sequence NAKTLAD (SEQ ID NO:74), and a lightchain variable region CDR3 comprising the amino acid sequence QHFWTSIT(SEQ ID NO:75); (d) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence DYYMN (SEQID NO:79), a heavy chain variable region CDR2 comprising the amino acidsequence DFNPNNGGTTYNQKFEG (SEQ ID NO:71) or DFNPNNAGTTYNQKFEG (SEQ IDNO:118), and a heavy chain variable region CDR3 comprising the aminoacid sequence GRFYYGSLYSFDY (SEQ ID NO:72), and a light chain variableregion comprising a light chain variable region CDR1 comprising theamino acid sequence RASGNIHNYLA (SEQ ID NO:73), a light chain variableregion CDR2 comprising the amino acid sequence NAKTLAD (SEQ ID NO:74),and a light chain variable region CDR3 comprising the amino acidsequence QHFWTSIT (SEQ ID NO:75); or (e) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence TDYYMN (SEQ ID NO:80), a heavy chain variable region CDR2comprising the amino acid sequence WIGDFNPNNGGTT (SEQ ID NO:81) or theamino acid sequence WIGDFNPNNAGTT (SEQ ID NO:121), and a heavy chainvariable region CDR3 comprising the amino acid sequence ARGRFYYGSLYSFD(SEQ ID NO:82), and a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequence HNYLAWY(SEQ ID NO:83), a light chain variable region CDR2 comprising the aminoacid sequence LLVYNAKTLA (SEQ ID NO:84) or the amino acid sequenceLLIYNAKTLA (SEQ ID NO:122), and a light chain variable region CDR3comprising the amino acid sequence QHFWTSI (SEQ ID NO:85).

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavychain variable region CDR2 comprising the amino acid sequenceDFNPNNGGTTYNQKFEG (SEQ ID NO:71) or DFNPNNAGTTYNQKFEG (SEQ ID NO:118),and a heavy chain variable region CDR3 comprising the amino acidsequence GRFYYGSLYSFDY (SEQ ID NO:72), and/or (b) a light chain variableregion comprising a light chain variable region CDR1 comprising theamino acid sequence RASGNIHNYLA (SEQ ID NO:73), a light chain variableregion CDR2 comprising the amino acid sequence NAKTLAD (SEQ ID NO:74),and a light chain variable region CDR3 comprising the amino acidsequence QHFWTSIT (SEQ ID NO:75). In some embodiments, theILT2/ILT4-binding agent comprises a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence GYTFTDYYMN (SEQ ID NO:70), a heavy chain variable region CDR2comprising the amino acid sequence DFNPNNGGTTYNQKFEG (SEQ ID NO:71), anda heavy chain variable region CDR3 comprising the amino acid sequenceGRFYYGSLYSFDY (SEQ ID NO:72). In some embodiments, the ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising a heavy chainvariable region CDR1 comprising the amino acid sequence GYTFTDYYMN (SEQID NO:70), a heavy chain variable region CDR2 comprising the amino acidsequence DFNPNNAGTTYNQKFEG (SEQ ID NO:118), and a heavy chain variableregion CDR3 comprising the amino acid sequence GRFYYGSLYSFDY (SEQ IDNO:72). In some embodiments, the ILT2/ILT4-binding agent comprises alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASGNIHNYLA (SEQ ID NO:73), alight chain variable region CDR2 comprising the amino acid sequenceNAKTLAD (SEQ ID NO:74), and a light chain variable region CDR3comprising the amino acid sequence QHFWTSIT (SEQ ID NO:75). In someembodiments, the ILT2/ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavy chainvariable region CDR2 comprising the amino acid sequenceDFNPNNGGTTYNQKFEG (SEQ ID NO:71), and a heavy chain variable region CDR3comprising the amino acid sequence GRFYYGSLYSFDY (SEQ ID NO:72), and (b)a light chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASGNIHNYLA (SEQ ID NO:73), alight chain variable region CDR2 comprising the amino acid sequenceNAKTLAD (SEQ ID NO:74), and a light chain variable region CDR3comprising the amino acid sequence QHFWTSIT (SEQ ID NO:75). In someembodiments, the ILT2/ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavy chainvariable region CDR2 comprising the amino acid sequenceDFNPNNAGTTYNQKFEG (SEQ ID NO:118), and a heavy chain variable regionCDR3 comprising the amino acid sequence GRFYYGSLYSFDY (SEQ ID NO:72),and (b) a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence RASGNIHNYLA (SEQ IDNO:73), a light chain variable region CDR2 comprising the amino acidsequence NAKTLAD (SEQ ID NO:74), and a light chain variable region CDR3comprising the amino acid sequence QHFWTSIT (SEQ ID NO:75).

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody 47H6 and which has atleast 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:131 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody 47H6 and which has at least 75%, at least80%, at least 85%, at least 90%, at least 95%, at least 96%, at least97%, at least 98%, at least 99%, or 100% identity to the sequence of SEQID NO:132.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:131. In some embodiments, an ILT2/ILT4-binding agent comprises alight chain variable region having at least 80%, at least 85%, at least90%, at least 95%, at least 97%, or at least 99% identity to thesequence of SEQ ID NO:132. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising an amino acidsequence of SEQ ID NO:131. In some embodiments, an ILT2/ILT4-bindingagent comprises a light chain variable region comprising an amino acidsequence of SEQ ID NO:132.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:131and a light chain variable region having at least 80% sequence identityto SEQ ID NO:132. In some embodiments, an ILT2/ILT4-binding agentcomprises a heavy chain variable region having at least 90% sequenceidentity to SEQ ID NO:131 and a light chain variable region having atleast 90% sequence identity to SEQ ID NO:132. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region havingat least 95% sequence identity to SEQ ID NO:131 and a light chainvariable region having at least 95% sequence identity to SEQ ID NO:132.In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising an amino acid sequence of SEQ ID NO:131 and alight chain variable region comprising an amino acid sequence of SEQ IDNO:132.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody Hz47H6.v2 and which hasat least 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:133 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody Hz47H6.v2 and which has at least 75%, atleast 80%, at least 85%, at least 90%, at least 95%, at least 96%, atleast 97%, at least 98%, at least 99%, or 100% identity to the sequenceof SEQ ID NO:134.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:133. In some embodiments, an ILT2/ILT4-binding agent comprises alight chain variable region having at least 80%, at least 85%, at least90%, at least 95%, at least 97%, or at least 99% identity to thesequence of SEQ ID NO:134. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising an amino acidsequence of SEQ ID NO:133. In some embodiments, an ILT2/ILT4-bindingagent comprises a light chain variable region comprising an amino acidsequence of SEQ ID NO:134.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:133and a light chain variable region having at least 80% sequence identityto SEQ ID NO:134. In some embodiments, an ILT2/ILT4-binding agentcomprises a heavy chain variable region having at least 90% sequenceidentity to SEQ ID NO:133 and a light chain variable region having atleast 90% sequence identity to SEQ ID NO:134. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region havingat least 95% sequence identity to SEQ ID NO:133 and a light chainvariable region having at least 95% sequence identity to SEQ ID NO:134.In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising an amino acid sequence of SEQ ID NO:133 and alight chain variable region comprising an amino acid sequence of SEQ IDNO:134.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chaincomprising a heavy chain variable region CDR1 comprising GYTFTDYYMN (SEQID NO:70), a heavy chain variable region CDR2 comprising the amino acidsequence DFNPNNGGTTYNQKFEG (SEQ ID NO:71) or DFNPNNAGTTYNQKFEG (SEQ IDNO:118), and a heavy chain variable region CDR3 comprising the aminoacid sequence GRFYYGSLYSFDY (SEQ ID NO:72), and a light chain comprisinga light chain variable region CDR1 comprising the amino acid sequenceRASGNIHNYLA (SEQ ID NO:73), a light chain variable region CDR2comprising the amino acid sequence NAKTLAD (SEQ ID NO:74), and a lightchain variable region CDR3 comprising the amino acid sequence QHFWTSIT(SEQ ID NO:75), wherein the heavy chain comprises at least 80%, at least85%, at least 90%, at least 95%, at least 97%, at least 98%, at least99%, or 100% identity to the sequence of SEQ ID NO:148, and wherein thelight chain comprises at least 80%, at least 85%, at least 90%, at least95%, at least 97%, at least 98%, at least 99%, or 100% identity to thesequence of SEQ ID NO:149. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain comprising a heavy chain variable regionCDR1 comprising GYTFTDYYMN (SEQ ID NO:70), a heavy chain variable regionCDR2 comprising the amino acid sequence DFNPNNGGTTYNQKFEG (SEQ ID NO:71)or DFNPNNAGTTYNQKFEG (SEQ ID NO:118), and a heavy chain variable regionCDR3 comprising the amino acid sequence GRFYYGSLYSFDY (SEQ ID NO:72),and a light chain comprising a light chain variable region CDR1comprising the amino acid sequence RASGNIHNYLA (SEQ ID NO:73), a lightchain variable region CDR2 comprising the amino acid sequence NAKTLAD(SEQ ID NO:74), and a light chain variable region CDR3 comprising theamino acid sequence QHFWTSIT (SEQ ID NO:75), wherein the heavy chaincomprises at least 95% identity to the sequence of SEQ ID NO:148, andwherein the light chain comprises at least 95% identity to the sequenceof SEQ ID NO:149. In some embodiments, an ILT2/ILT4-binding agentcomprises (a) a heavy chain comprising the amino acids of SEQ ID NO:148and (b) a light chain comprising a light chain variable region CDR1comprising RASGNIHNYLA (SEQ ID NO:73), a light chain variable regionCDR2 comprising the amino acid sequence NAKTLAD (SEQ ID NO:74), and alight chain variable region CDR3 comprising the amino acid sequenceQHFWTSIT (SEQ ID NO:75), wherein the light chain comprises at least 80%,at least 85%, at least 90%, at least 95%, at least 97%, at least 98%, atleast 99%, or 100% identity to the sequence of SEQ ID NO:149. In someembodiments, an ILT2/ILT4-binding agent comprises (a) a heavy chaincomprising the amino acids of SEQ ID NO:148 and (b) a light chaincomprising a light chain variable region CDR1 comprising RASGNIHNYLA(SEQ ID NO:73), a light chain variable region CDR2 comprising the aminoacid sequence NAKTLAD (SEQ ID NO:74), and a light chain variable regionCDR3 comprising the amino acid sequence QHFWTSIT (SEQ ID NO:75). In someembodiments, an ILT2/ILT4-binding agent comprises (a) a heavy chaincomprising a heavy chain variable region CDR1 comprising GYTFTDYYMN (SEQID NO:70), a heavy chain variable region CDR2 comprising the amino acidsequence DFNPNNGGTTYNQKFEG (SEQ ID NO:71) or DFNPNNAGTTYNQKFEG (SEQ IDNO:118), and a heavy chain variable region CDR3 comprising the aminoacid sequence GRFYYGSLYSFDY (SEQ ID NO:72), wherein the heavy chaincomprises at least 80%, at least 85%, at least 90%, at least 95%, atleast 97%, at least 98%, at least 99%, or 100% identity to the sequenceof SEQ ID NO:148, and (b) a light chain comprising the amino acidsequence of SEQ ID NO:149. In some embodiments, an ILT2/ILT4-bindingagent comprises (a) a heavy chain comprising a heavy chain variableregion CDR1 comprising GYTFTDYYMN (SEQ ID NO:70), a heavy chain variableregion CDR2 comprising the amino acid sequence DFNPNNGGTTYNQKFEG (SEQ IDNO:71) or DFNPNNAGTTYNQKFEG (SEQ ID NO:118), and a heavy chain variableregion CDR3 comprising the amino acid sequence GRFYYGSLYSFDY (SEQ IDNO:72), and (b) a light chain comprising the amino acid sequence of SEQID NO:149. In some embodiments, an ILT2/ILT4-binding agent is anantibody comprising a heavy chain comprising the amino acid sequence ofSEQ ID NO:148 and a light chain comprising the amino acid sequence ofSEQ ID NO:149.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainhaving at least 80%, at least 85%, at least 90%, or at least 95%identity to the amino acid sequence of SEQ ID NO:148. In someembodiments, an ILT2/ILT4-binding agent comprises a light chain havingat least 80%, at least 85%, at least 90%, or at least 95% identity tothe amino acid sequence of SEQ ID NO:149. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain having at least 80%, atleast 85%, at least 90%, or at least 95% identity to the amino acidsequence of SEQ ID NO:148 and a light chain having at least 80%, atleast 85%, at least 90%, or at least 95% identity to the amino acidsequence of SEQ ID NO:149. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain having at least 90% identity to the aminoacid sequence of SEQ ID NO:148. In some embodiments, anILT2/ILT4-binding agent comprises a light chain having at least 90%identity to the amino acid sequence of SEQ ID NO:149. In someembodiments, an ILT2/ILT4-binding agent comprises a heavy chain havingat least 90% identity to the amino acid sequence of SEQ ID NO:148 and alight chain having at least 90% identity to the amino acid sequence ofSEQ ID NO:149. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain comprising the amino acid sequence of SEQ ID NO:148. Insome embodiments, an ILT2/ILT4-binding agent comprises a light chaincomprising the amino acid sequence of SEQ ID NO:149. In someembodiments, an ILT2/ILT4-binding agent comprises a heavy chaincomprising the amino acid sequence of SEQ ID NO:148 and a light chaincomprising the amino acid sequence of SEQ ID NO:149. In someembodiments, an ILT2/ILT4-binding agent is an antibody that comprises aheavy chain of SEQ ID NO:148 and/or a light chain of SEQ ID NO:149. Insome embodiments, an ILT2/ILT4-binding agent is an antibody thatcomprises a heavy chain of SEQ ID NO:148. In some embodiments, anILT2/ILT4-binding agent is an antibody that comprises a light chain ofSEQ ID NO:149. In some embodiments, an ILT2/ILT4-binding agent is anantibody that comprises a heavy chain of SEQ ID NO:148 and a light chainof SEQ ID NO:149.

In some embodiments, an ILT2/ILT4-binding agent (e.g., a dual binder)comprises a heavy chain variable region CDR1, CDR2, and CDR3 and/or alight chain variable region CDR1, CDR2, and CDR3 from antibody 51A1, ahumanized version thereof, or variants thereof. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable regioncomprising a heavy chain variable region CDR1, a heavy chain variableregion CDR2, and a heavy chain variable region CDR3 from antibody 51A1.In other embodiments, an ILT2/ILT4-binding agent comprises a light chainvariable region comprising a light chain variable region CDR1, a lightchain variable region CDR2, and a light chain variable region CDR3 fromantibody 51A1. In some embodiments, an ILT2/ILT4-binding agentcomprises: (a) a heavy chain variable region comprising a heavy chainvariable region CDR1, a heavy chain variable region CDR2, a heavy chainvariable region CDR3; and (b) a light chain variable region comprising alight chain variable region CDR1, a light chain variable region CDR2,and a light chain variable region CDR3 from antibody 51A1. In someembodiments, an ILT2/ILT4-binding agent is a humanized version ofantibody 51A1. In some embodiments, an ILT2/ILT4-binding agent is avariant of antibody 51A1 or humanized 51A1.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavychain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYGTMYYYAMDY (SEQ ID NO:88),and a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence RASESVDYYGNSFMY (SEQ IDNO:89), a light chain variable region CDR2 comprising the amino acidsequence FASNLES (SEQ ID NO:90), and a light chain variable region CDR3comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91); (b) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFTFNTY (SEQ ID NO:92), a heavy chainvariable region CDR2 comprising the amino acid sequence RSKSSNYA (SEQ IDNO:93), and a heavy chain variable region CDR3 comprising the amino acidsequence DGIYYYGTMYYYAMDY (SEQ ID NO:88), and a light chain variableregion comprising a light chain variable region CDR1 comprising theamino acid sequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chainvariable region CDR2 comprising the amino acid sequence FASNLES (SEQ IDNO:90), and a light chain variable region CDR3 comprising the amino acidsequence QQNNEDPWT (SEQ ID NO:91); (c) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence GFTFNTYAMH (SEQ ID NO:86), a heavy chain variable region CDR2comprising the amino acid sequence RIRSKSSNYATY (SEQ ID NO:94), and aheavy chain variable region CDR3 comprising the amino acid sequenceDGIYYYGTMYYYAMDY (SEQ ID NO:88), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable regionCDR2 comprising the amino acid sequence FASNLES (SEQ ID NO:90), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPWT (SEQ ID NO:91); (d) a heavy chain variable region comprising aheavy chain variable region CDR1 comprising the amino acid sequenceTYAMH (SEQ ID NO:95), a heavy chain variable region CDR2 comprising theamino acid sequence RIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavychain variable region CDR3 comprising the amino acid sequenceDGIYYYGTMYYYAMDY (SEQ ID NO:88), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable regionCDR2 comprising the amino acid sequence FASNLES (SEQ ID NO:90), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPWT (SEQ ID NO:91); or (e) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence NTYAMH (SEQ ID NO:96), a heavy chain variable region CDR2comprising the amino acid sequence WVARIRSKSSNYATY (SEQ ID NO:97), and aheavy chain variable region CDR3 comprising the amino acid sequenceVRDGIYYYGTMYYYAMD (SEQ ID NO:98), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence DYYGNSFMYWY (SEQ ID NO:99), a light chain variable region CDR2comprising the amino acid sequence LLIYFASNLE (SEQ ID NO:100), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPW (SEQ ID NO:101).

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavychain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYGTMYYYAMDY (SEQ ID NO:88),and/or (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). Insome embodiments, the ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavy chainvariable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYGTMYYYAMDY (SEQ ID NO:88).In some embodiments, the ILT2/ILT4-binding agent comprises a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chainvariable region CDR2 comprising the amino acid sequence FASNLES (SEQ IDNO:90), and a light chain variable region CDR3 comprising the amino acidsequence QQNNEDPWT (SEQ ID NO:91). In some embodiments, theILT2/ILT4-binding agent comprises: (a) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence GFTFNTYAMH (SEQ ID NO:86), a heavy chain variable region CDR2comprising the amino acid sequence RIRSKSSNYATYYADSVKD (SEQ ID NO:87),and a heavy chain variable region CDR3 comprising the amino acidsequence DGIYYYGTMYYYAMDY (SEQ ID NO:88), and (b) a light chain variableregion comprising a light chain variable region CDR1 comprising theamino acid sequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chainvariable region CDR2 comprising the amino acid sequence FASNLES (SEQ IDNO:90), and a light chain variable region CDR3 comprising the amino acidsequence QQNNEDPWT (SEQ ID NO:91).

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody 51A1 and which has atleast 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:135 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody 51A1 and which has at least 75%, at least80%, at least 85%, at least 90%, at least 95%, at least 96%, at least97%, at least 98%, at least 99%, or 100% identity to the sequence of SEQID NO:136.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:135. In some embodiments, an ILT2/ILT4-binding agent comprises alight chain variable region having at least 80%, at least 85%, at least90%, at least 95%, at least 97%, or at least 99% identity to thesequence of SEQ ID NO:136. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising an amino acidsequence of SEQ ID NO:135. In some embodiments, an ILT2/ILT4-bindingagent comprises a light chain variable region comprising an amino acidsequence of SEQ ID NO:136.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:135and a light chain variable region having at least 80% sequence identityto SEQ ID NO:136. In some embodiments, an ILT2/ILT4-binding agentcomprises a heavy chain variable region having at least 90% sequenceidentity to SEQ ID NO:135 and a light chain variable region having atleast 90% sequence identity to SEQ ID NO:136. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region havingat least 95% sequence identity to SEQ ID NO:135 and a light chainvariable region having at least 95% sequence identity to SEQ ID NO:136.In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising an amino acid sequence of SEQ ID NO:135 and alight chain variable region comprising an amino acid sequence of SEQ IDNO:136.

In some embodiments, an ILT2/ILT4-binding agent (e.g., a dual binder)comprises a heavy chain variable region CDR1, CDR2, and CDR3 and/or alight chain variable region CDR1, CDR2, and CDR3 from antibody 64A12, ahumanized version thereof (e.g., Hz64A12), or variants thereof. In someembodiments, an ILT2/ILT4-binding agent comprises a heavy chain variableregion comprising a heavy chain variable region CDR1, a heavy chainvariable region CDR2, and a heavy chain variable region CDR3 fromantibody 64A12 or Hz64A12. In other embodiments, an ILT2/ILT4-bindingagent comprises a light chain variable region comprising a light chainvariable region CDR1, a light chain variable region CDR2, and a lightchain variable region CDR3 from antibody 64A12 or Hz64A12. In someembodiments, an ILT2/ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1, a heavychain variable region CDR2, a heavy chain variable region CDR3; and (b)a light chain variable region comprising a light chain variable regionCDR1, a light chain variable region CDR2, and a light chain variableregion CDR3 from antibody 64A12 or Hz64A12. In some embodiments, anILT2/ILT4-binding agent is a humanized version of antibody 64A12. Insome embodiments, an ILT2/ILT4-binding agent is a variant of antibody64A12. In some embodiments, an ILT2/ILT4-binding agent is a variant ofantibody Hz64A12.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavychain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYDTMYYYAMDY (SEQ IDNO:102), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFIY(SEQ ID NO:103), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91); (b) aheavy chain variable region comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GFTFNTY (SEQ ID NO:92), a heavychain variable region CDR2 comprising the amino acid sequence RSKSSNYA(SEQ ID NO:93), and a heavy chain variable region CDR3 comprising theamino acid sequence DGIYYYDTMYYYAMDY (SEQ ID NO:102), and a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASESVDYYGNSFIY (SEQ ID NO:103), a light chainvariable region CDR2 comprising the amino acid sequence FASNLES (SEQ IDNO:90), and a light chain variable region CDR3 comprising the amino acidsequence QQNNEDPWT (SEQ ID NO:91); (c) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence GFTFNTYAMH (SEQ ID NO:86), a heavy chain variable region CDR2comprising the amino acid sequence RIRSKSSNYATY (SEQ ID NO:94), and aheavy chain variable region CDR3 comprising the amino acid sequenceDGIYYYDTMYYYAMDY (SEQ ID NO:102), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence RASESVDYYGNSFIY (SEQ ID NO:103), a light chain variable regionCDR2 comprising the amino acid sequence FASNLES (SEQ ID NO:90), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPWT (SEQ ID NO:91); (d) a heavy chain variable region comprising aheavy chain variable region CDR1 comprising the amino acid sequenceTYAMH (SEQ ID NO:95), a heavy chain variable region CDR2 comprising theamino acid sequence RIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavychain variable region CDR3 comprising the amino acid sequenceDGIYYYDTMYYYAMDY (SEQ ID NO:102), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence RASESVDYYGNSFIY (SEQ ID NO:103), a light chain variable regionCDR2 comprising the amino acid sequence FASNLES (SEQ ID NO:90), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPWT (SEQ ID NO:91); or (e) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence NTYAMH (SEQ ID NO:96), a heavy chain variable region CDR2comprising the amino acid sequence WVARIRSKSSNYATY (SEQ ID NO:97), and aheavy chain variable region CDR3 comprising the amino acid sequenceVRDGIYYYDTMYYYAMD (SEQ ID NO:104), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence DYYGNSFIYWY (SEQ ID NO:105), a light chain variable region CDR2comprising the amino acid sequence LLIYFASNLE (SEQ ID NO:100), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPW (SEQ ID NO:101).

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavychain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYDTMYYYAMDY (SEQ IDNO:102), and/or (b) a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFIY (SEQ ID NO:103), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91). In some embodiments, the ILT2/ILT4-binding agentcomprises a heavy chain variable region comprising a heavy chainvariable region CDR1 comprising the amino acid sequence GFTFNTYAMH (SEQID NO:86), a heavy chain variable region CDR2 comprising the amino acidsequence RIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variableregion CDR3 comprising the amino acid sequence DGIYYYDTMYYYAMDY (SEQ IDNO:102). In some embodiments, the ILT2/ILT4-binding agent comprises alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASESVDYYGNSFIY (SEQ ID NO:103),a light chain variable region CDR2 comprising the amino acid sequenceFASNLES (SEQ ID NO:90), and a light chain variable region CDR3comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). In someembodiments, the ILT2/ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavy chainvariable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYDTMYYYAMDY (SEQ IDNO:102), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFIY(SEQ ID NO:103), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91).

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody 64A12 and which has atleast 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:137 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody 64A12 and which has at least 75%, at least80%, at least 85%, at least 90%, at least 95%, at least 96%, at least97%, at least 98%, at least 99%, or 100% identity to the sequence of SEQID NO:138.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:137. In some embodiments, an ILT2/ILT4-binding agent comprises alight chain variable region having at least 80%, at least 85%, at least90%, at least 95%, at least 97%, or at least 99% identity to thesequence of SEQ ID NO:138. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising an amino acidsequence of SEQ ID NO:137. In some embodiments, an ILT2/ILT4-bindingagent comprises a light chain variable region comprising an amino acidsequence of SEQ ID NO:138.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:137and a light chain variable region having at least 80% sequence identityto SEQ ID NO:138. In some embodiments, an ILT2/ILT4-binding agentcomprises a heavy chain variable region having at least 90% sequenceidentity to SEQ ID NO:137 and a light chain variable region having atleast 90% sequence identity to SEQ ID NO:138. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region havingat least 95% sequence identity to SEQ ID NO:137 and a light chainvariable region having at least 95% sequence identity to SEQ ID NO:138.In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising an amino acid sequence of SEQ ID NO:137 and alight chain variable region comprising an amino acid sequence of SEQ IDNO:138.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody Hz64A12 and which hasat least 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:139 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody Hz64A12 and which has at least 75%, at least80%, at least 85%, at least 90%, at least 95%, at least 96%, at least97%, at least 98%, at least 99%, or 100% identity to the sequence of SEQID NO:140.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:139. In some embodiments, an ILT2/ILT4-binding agent comprises alight chain variable region having at least 80%, at least 85%, at least90%, at least 95%, at least 97%, or at least 99% identity to thesequence of SEQ ID NO:140. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising an amino acidsequence of SEQ ID NO:139. In some embodiments, an ILT2/ILT4-bindingagent comprises a light chain variable region comprising an amino acidsequence of SEQ ID NO:140.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:139and a light chain variable region having at least 80% sequence identityto SEQ ID NO:140. In some embodiments, an ILT2/ILT4-binding agentcomprises a heavy chain variable region having at least 90% sequenceidentity to SEQ ID NO:139 and a light chain variable region having atleast 90% sequence identity to SEQ ID NO:140. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region havingat least 95% sequence identity to SEQ ID NO:139 and a light chainvariable region having at least 95% sequence identity to SEQ ID NO:140.In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising an amino acid sequence of SEQ ID NO:139 and alight chain variable region comprising an amino acid sequence of SEQ IDNO:140.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chaincomprising a heavy chain variable region CDR1 comprising the amino acidsequence GFTFNTYAMH (SEQ ID NO:86), a heavy chain variable region CDR2comprising the amino acid sequence RIRSKSSNYATYYADSVKD (SEQ ID NO:87),and a heavy chain variable region CDR3 comprising the amino acidsequence DGIYYYDTMYYYAMDY (SEQ ID NO:102), and a light chain comprisinga light chain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFIY (SEQ ID NO:103), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91), wherein the heavy chain comprises at least 80%, at least85%, at least 90%, at least 95%, at least 97%, at least 98%, at least99%, or 100% identity to the sequence of SEQ ID NO:152, and wherein thelight chain comprises at least 80%, at least 85%, at least 90%, at least95%, at least 97%, at least 98%, at least 99%, or 100% identity to thesequence of SEQ ID NO:153. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), aheavy chain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYDTMYYYAMDY (SEQ IDNO:102), and a light chain comprising a light chain variable region CDR1comprising the amino acid sequence RASESVDYYGNSFIY (SEQ ID NO:103), alight chain variable region CDR2 comprising the amino acid sequenceFASNLES (SEQ ID NO:90), and a light chain variable region CDR3comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91), wherein theheavy chain comprises at least 95% identity to the sequence of SEQ IDNO:152, and wherein the light chain comprises at least 95% identity tothe sequence of SEQ ID NO:153. In some embodiments, an ILT2/ILT4-bindingagent comprises (a) a heavy chain comprising the amino acids of SEQ IDNO:152 and (b) a light chain comprising a light chain variable regionCDR1 comprising the amino acid sequence RASESVDYYGNSFIY (SEQ ID NO:103),a light chain variable region CDR2 comprising the amino acid sequenceFASNLES (SEQ ID NO:90), and a light chain variable region CDR3comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91), wherein thelight chain comprises at least 80%, at least 85%, at least 90%, at least95%, at least 97%, at least 98%, at least 99%, or 100% identity to thesequence of SEQ ID NO:153. In some embodiments, an ILT2/ILT4-bindingagent comprises (a) a heavy chain comprising the amino acids of SEQ IDNO:152 and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFIY(SEQ ID NO:103), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). Insome embodiments, an ILT2/ILT4-binding agent comprises (a) a heavy chaincomprising a heavy chain variable region CDR1 comprising the amino acidsequence GFTFNTYAMH (SEQ ID NO:86), a heavy chain variable region CDR2comprising the amino acid sequence RIRSKSSNYATYYADSVKD (SEQ ID NO:87),and a heavy chain variable region CDR3 comprising the amino acidsequence DGIYYYDTMYYYAMDY (SEQ ID NO:102), wherein the heavy chaincomprises at least 80%, at least 85%, at least 90%, at least 95%, atleast 97%, at least 98%, at least 99%, or 100% identity to the sequenceof SEQ ID NO:152, and (b) a light chain comprising the amino acidsequence of SEQ ID NO:153. In some embodiments, an ILT2/ILT4-bindingagent comprises (a) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence GFTFNTYAMH(SEQ ID NO:86), a heavy chain variable region CDR2 comprising the aminoacid sequence RIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chainvariable region CDR3 comprising the amino acid sequence DGIYYYDTMYYYAMDY(SEQ ID NO:102), and (b) a light chain comprising the amino acidsequence of SEQ ID NO:153. In some embodiments, an ILT2/ILT4-bindingagent is an antibody comprising a heavy chain comprising the amino acidsequence of SEQ ID NO:152 and a light chain comprising the amino acidsequence of SEQ ID NO:153.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainhaving at least 80%, at least 85%, at least 90%, or at least 95%identity to the amino acid sequence of SEQ ID NO:152. In someembodiments, an ILT2/ILT4-binding agent comprises a light chain havingat least 80%, at least 85%, at least 90%, or at least 95% identity tothe amino acid sequence of SEQ ID NO:153. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain having at least 80%, atleast 85%, at least 90%, or at least 95% identity to the amino acidsequence of SEQ ID NO:152 and a light chain having at least 80%, atleast 85%, at least 90%, or at least 95% identity to the amino acidsequence of SEQ ID NO:153. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain having at least 90% identity to the aminoacid sequence of SEQ ID NO:152. In some embodiments, anILT2/ILT4-binding agent comprises a light chain having at least 90%identity to the amino acid sequence of SEQ ID NO:153. In someembodiments, an ILT2/ILT4-binding agent comprises a heavy chain havingat least 90% identity to the amino acid sequence of SEQ ID NO:152 and alight chain having at least 90% identity to the amino acid sequence ofSEQ ID NO:153. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain comprising the amino acid sequence of SEQ ID NO:152. Insome embodiments, an ILT2/ILT4-binding agent comprises a light chaincomprising the amino acid sequence of SEQ ID NO:153. In someembodiments, an ILT2/ILT4-binding agent comprises a heavy chaincomprising the amino acid sequence of SEQ ID NO:152 and a light chaincomprising the amino acid sequence of SEQ ID NO:153. In someembodiments, an ILT2/ILT4-binding agent is an antibody that comprises aheavy chain of SEQ ID NO:152 and/or a light chain of SEQ ID NO:153. Insome embodiments, an ILT2/ILT4-binding agent is an antibody thatcomprises a heavy chain of SEQ ID NO:152. In some embodiments, anILT2/ILT4-binding agent is an antibody that comprises a light chain ofSEQ ID NO:153. In some embodiments, an ILT2/ILT4-binding agent is anantibody that comprises a heavy chain of SEQ ID NO:152 and a light chainof SEQ ID NO:153.

In some embodiments, an ILT2/ILT4-binding agent (e.g., a dual binder)comprises a heavy chain variable region CDR1, CDR2, and CDR3 and/or alight chain variable region CDR1, CDR2, and CDR3 from antibody 73C4, ahumanized version thereof, or variants thereof. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable regioncomprising a heavy chain variable region CDR1, a heavy chain variableregion CDR2, and a heavy chain variable region CDR3 from antibody 73C4.In other embodiments, an ILT2/ILT4-binding agent comprises a light chainvariable region comprising a light chain variable region CDR1, a lightchain variable region CDR2, and a light chain variable region CDR3 fromantibody 73C4. In some embodiments, an ILT2/ILT4-binding agentcomprises: (a) a heavy chain variable region comprising a heavy chainvariable region CDR1, a heavy chain variable region CDR2, a heavy chainvariable region CDR3; and (b) a light chain variable region comprising alight chain variable region CDR1, a light chain variable region CDR2,and a light chain variable region CDR3 from antibody 73C4. In someembodiments, an ILT2/ILT4-binding agent is a humanized version ofantibody 73C4. In some embodiments, an ILT2/ILT4-binding agent is avariant of antibody 73C4 or humanized 73C4.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavychain variable region CDR2 comprising the amino acid sequenceNVNPNNGGTSYNQKFKG (SEQ ID NO:106), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91); (b) aheavy chain variable region comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GYTFTDY (SEQ ID NO:76), a heavychain variable region CDR2 comprising the amino acid sequence NPNNGG(SEQ ID NO:77), and a heavy chain variable region CDR3 comprising theamino acid sequence REIYFYGTIYYYAMDY (SEQ ID NO:107), and a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chainvariable region CDR2 comprising the amino acid sequence FASNLES (SEQ IDNO:90), and a light chain variable region CDR3 comprising the amino acidsequence QQNNEDPWT (SEQ ID NO:91); (c) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence GYTFTDYYMN (SEQ ID NO:70), a heavy chain variable region CDR2comprising the amino acid sequence NVNPNNGGTS (SEQ ID NO:108), and aheavy chain variable region CDR3 comprising the amino acid sequenceREIYFYGTIYYYAMDY (SEQ ID NO:107), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable regionCDR2 comprising the amino acid sequence FASNLES (SEQ ID NO:90), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPWT (SEQ ID NO:91); (d) a heavy chain variable region comprising aheavy chain variable region CDR1 comprising the amino acid sequenceDYYMN (SEQ ID NO:79), a heavy chain variable region CDR2 comprising theamino acid sequence NVNPNNGGTSYNQKFKG (SEQ ID NO:106), and a heavy chainvariable region CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY(SEQ ID NO:107), and a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91); or (e) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence TDYYMN(SEQ ID NO:80), a heavy chain variable region CDR2 comprising the aminoacid sequence WIGNVNPNNGGTS (SEQ ID NO:109), and a heavy chain variableregion CDR3 comprising the amino acid sequence ARREIYFYGTIYYYAMD (SEQ IDNO:110), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence DYYGNSFMYWY (SEQID NO:99), a light chain variable region CDR2 comprising the amino acidsequence LLIYFASNLE (SEQ ID NO:100), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPW (SEQ ID NO:101).

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavychain variable region CDR2 comprising the amino acid sequenceNVNPNNGGTSYNQKFKG (SEQ ID NO:106), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and/or (b) a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91). In some embodiments, the ILT2/ILT4-binding agentcomprises a heavy chain variable region comprising a heavy chainvariable region CDR1 comprising the amino acid sequence GYTFTDYYMN (SEQID NO:70), a heavy chain variable region CDR2 comprising the amino acidsequence NVNPNNGGTSYNQKFKG (SEQ ID NO:106), and a heavy chain variableregion CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107). In some embodiments, the ILT2/ILT4-binding agent comprises alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASESVDYYGNSFMY (SEQ ID NO:89),a light chain variable region CDR2 comprising the amino acid sequenceFASNLES (SEQ ID NO:90), and a light chain variable region CDR3comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). In someembodiments, the ILT2/ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavy chainvariable region CDR2 comprising the amino acid sequenceNVNPNNGGTSYNQKFKG (SEQ ID NO:106), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91).

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody 73C4 and which has atleast 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:141 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody 73C4 and which has at least 75%, at least80%, at least 85%, at least 90%, at least 95%, at least 96%, at least97%, at least 98%, at least 99%, or 100% identity to the sequence of SEQID NO:142.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:141. In some embodiments, an ILT2/ILT4-binding agent comprises alight chain variable region having at least 80%, at least 85%, at least90%, at least 95%, at least 97%, or at least 99% identity to thesequence of SEQ ID NO:142. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising an amino acidsequence of SEQ ID NO:141. In some embodiments, an ILT2/ILT4-bindingagent comprises a light chain variable region comprising an amino acidsequence of SEQ ID NO:142.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:141and a light chain variable region having at least 80% sequence identityto SEQ ID NO:142. In some embodiments, an ILT2/ILT4-binding agentcomprises a heavy chain variable region having at least 90% sequenceidentity to SEQ ID NO:141 and a light chain variable region having atleast 90% sequence identity to SEQ ID NO:142. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region havingat least 95% sequence identity to SEQ ID NO:141 and a light chainvariable region having at least 95% sequence identity to SEQ ID NO:142.In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising an amino acid sequence of SEQ ID NO:141 and alight chain variable region comprising an amino acid sequence of SEQ IDNO:142.

In some embodiments, an ILT2/ILT4-binding agent (e.g., a dual binder)comprises a heavy chain variable region CDR1, CDR2, and CDR3 and/or alight chain variable region CDR1, CDR2, and CDR3 from antibody 73D1, ahumanized version thereof (e.g., Hz73D1), or variants thereof. In someembodiments, an ILT2/ILT4-binding agent comprises a heavy chain variableregion comprising a heavy chain variable region CDR1, a heavy chainvariable region CDR2, and a heavy chain variable region CDR3 fromantibody 73D1 or antibody Hz73D1.v1. In other embodiments, anILT2/ILT4-binding agent comprises a light chain variable regioncomprising a light chain variable region CDR1, a light chain variableregion CDR2, and a light chain variable region CDR3 from antibody 73D1or antibody Hz73D1.v1. In some embodiments, an ILT2/ILT4-binding agentcomprises: (a) a heavy chain variable region comprising a heavy chainvariable region CDR1, a heavy chain variable region CDR2, a heavy chainvariable region CDR3; and (b) a light chain variable region comprising alight chain variable region CDR1, a light chain variable region CDR2,and a light chain variable region CDR3 from antibody 73D1 or antibodyHz73D1.v1. In some embodiments, an ILT2/ILT4-binding agent is ahumanized version of antibody 73D1. In some embodiments, anILT2/ILT4-binding agent is a variant of antibody 73D1. In someembodiments, an ILT2/ILT4-binding agent is a variant of antibodyHz73D1.v1.

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYIN (SEQ ID NO:111), a heavychain variable region CDR2 comprising the amino acid sequenceNVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91); (b) aheavy chain variable region comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GYTFTDY (SEQ ID NO:76), a heavychain variable region CDR2 comprising the amino acid sequence NPNDGG(SEQ ID NO:113), and a heavy chain variable region CDR3 comprising theamino acid sequence REIYFYGTIYYYAMDY (SEQ ID NO:107), and a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chainvariable region CDR2 comprising the amino acid sequence FASNLES (SEQ IDNO:90), and a light chain variable region CDR3 comprising the amino acidsequence QQNNEDPWT (SEQ ID NO:91); (c) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence GYTFTDYYIN (SEQ ID NO:111), a heavy chain variable region CDR2comprising the amino acid sequence NVNPNDGGTT (SEQ ID NO:114), and aheavy chain variable region CDR3 comprising the amino acid sequenceREIYFYGTIYYYAMDY (SEQ ID NO:107), and a light chain variable regioncomprising a light chain variable region CDR1 comprising the amino acidsequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable regionCDR2 comprising the amino acid sequence FASNLES (SEQ ID NO:90), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPWT (SEQ ID NO:91); (d) a heavy chain variable region comprising aheavy chain variable region CDR1 comprising the amino acid sequenceDYYIN (SEQ ID NO:115), a heavy chain variable region CDR2 comprising theamino acid sequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chainvariable region CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY(SEQ ID NO:107), and a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91); or (e) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence TDYYIN(SEQ ID NO:116), a heavy chain variable region CDR2 comprising the aminoacid sequence WIGNVNPNDGGTT (SEQ ID NO:117) or the amino acid sequenceWMGNVNPNDGGTT (SEQ ID NO:124), and a heavy chain variable region CDR3comprising the amino acid sequence ARREIYFYGTIYYYAMD (SEQ ID NO:110),and a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence DYYGNSFMYWY (SEQ IDNO:99), a light chain variable region CDR2 comprising the amino acidsequence LLIYFASNLE (SEQ ID NO:100), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPW (SEQ ID NO:101).

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYIN (SEQ ID NO:111), a heavychain variable region CDR2 comprising the amino acid sequenceNVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and/or (b) a light chain variable region comprising a lightchain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91). In some embodiments, the ILT2/ILT4-binding agentcomprises a heavy chain variable region comprising a heavy chainvariable region CDR1 comprising the amino acid sequence GYTFTDYYIN (SEQID NO:111), a heavy chain variable region CDR2 comprising the amino acidsequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chain variableregion CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107). In some embodiments, the ILT2/ILT4-binding agent comprises alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASESVDYYGNSFMY (SEQ ID NO:89),a light chain variable region CDR2 comprising the amino acid sequenceFASNLES (SEQ ID NO:90), and a light chain variable region CDR3comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). In someembodiments, the ILT2/ILT4-binding agent comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYTFTDYYIN (SEQ ID NO:111), a heavy chainvariable region CDR2 comprising the amino acid sequenceNVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91).

In some embodiments, an ILT2/ILT4-binding agent comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYIN (SEQ ID NO:111), or avariant thereof comprising 1, 2, 3, or 4 amino acid substitutions; aheavy chain variable region CDR2 comprising the amino acid sequenceNVNPNDGGTTYNQKFKG (SEQ ID NO:112), or a variant thereof comprising 1, 2,3, or 4 amino acid substitutions; and a heavy chain variable region CDR3comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ ID NO:107), ora variant thereof comprising 1, 2, 3, or 4 amino acid substitutions; and(b) a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence RASESVDYYGNSFMY (SEQ IDNO:89), or a variant thereof comprising 1, 2, 3, or 4 amino acidsubstitutions; a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), or a variant thereof comprising 1,2, 3, or 4 amino acid substitutions; and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91), or avariant thereof comprising 1, 2, 3, or 4 amino acid substitutions.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody 73D1 and which has atleast 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:143 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody 73D1 and which has at least 75%, at least80%, at least 85%, at least 90%, at least 95%, at least 96%, at least97%, at least 98%, at least 99%, or 100% identity to the sequence of SEQID NO:142.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:143. In some embodiments, an ILT2/ILT4-binding agent comprises alight chain variable region having at least 80%, at least 85%, at least90%, at least 95%, at least 97%, or at least 99% identity to thesequence of SEQ ID NO:142. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising an amino acidsequence of SEQ ID NO:143. In some embodiments, an ILT2/ILT4-bindingagent comprises a light chain variable region comprising an amino acidsequence of SEQ ID NO:142.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:143and a light chain variable region having at least 80% sequence identityto SEQ ID NO:142. In some embodiments, an ILT2/ILT4-binding agentcomprises a heavy chain variable region having at least 90% sequenceidentity to SEQ ID NO:143 and a light chain variable region having atleast 90% sequence identity to SEQ ID NO:142. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region havingat least 95% sequence identity to SEQ ID NO:143 and a light chainvariable region having at least 95% sequence identity to SEQ ID NO:142.In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising an amino acid sequence of SEQ ID NO:143 and alight chain variable region comprising an amino acid sequence of SEQ IDNO:142.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising the amino acid sequence of heavy chainvariable region CDR1, CDR2, and CDR3 of antibody Hz73D1.v1 and which hasat least 75%, at least 80%, at least 85%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99%, or 100% identity tothe sequence of SEQ ID NO:144 and a light chain variable regioncomprising the amino acid sequence of light chain variable region CDR1,CDR2, and CDR3 of antibody Hz73D1.v1 and which has at least 75%, atleast 80%, at least 85%, at least 90%, at least 95%, at least 96%, atleast 97%, at least 98%, at least 99%, or 100% identity to the sequenceof SEQ ID NO:145.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80%, at least 85%, at least 90%, atleast 95%, at least 97%, or at least 99% identity to the sequence of SEQID NO:144. In some embodiments, an ILT2/ILT4-binding agent comprises alight chain variable region having at least 80%, at least 85%, at least90%, at least 95%, at least 97%, or at least 99% identity to thesequence of SEQ ID NO:145. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain variable region comprising an amino acidsequence of SEQ ID NO:144. In some embodiments, an ILT2/ILT4-bindingagent comprises a light chain variable region comprising an amino acidsequence of SEQ ID NO:145.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region having at least 80% sequence identity to SEQ ID NO:144and a light chain variable region having at least 80% sequence identityto SEQ ID NO:145. In some embodiments, an ILT2/ILT4-binding agentcomprises a heavy chain variable region having at least 90% sequenceidentity to SEQ ID NO:144 and a light chain variable region having atleast 90% sequence identity to SEQ ID NO:145. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable region havingat least 95% sequence identity to SEQ ID NO:144 and a light chainvariable region having at least 95% sequence identity to SEQ ID NO:145.In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising an amino acid sequence of SEQ ID NO:144 and alight chain variable region comprising an amino acid sequence of SEQ IDNO:145.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingGYTFTDYYIN (SEQ ID NO:111), a heavy chain variable region CDR2comprising the amino acid sequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112),and a heavy chain variable region CDR3 comprising the amino acidsequence REIYFYGTIYYYAMDY (SEQ ID NO:107), and a light chain variableregion comprising a light chain variable region CDR1 comprising theamino acid sequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chainvariable region CDR2 comprising the amino acid sequence FASNLES (SEQ IDNO:90), and a light chain variable region CDR3 comprising the amino acidsequence QQNNEDPWT (SEQ ID NO:91), wherein the heavy chain variableregion comprises at least 80%, at least 85%, at least 90%, at least 95%,at least 97%, at least 98% identity to the sequence of SEQ ID NO:143,and wherein the light chain variable region comprises at least 80%, atleast 85%, at least 90%, at least 95%, at least 97%, at least 98%identity to the sequence of SEQ ID NO:142. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising GYTFTDYYIN (SEQID NO:111), a heavy chain variable region CDR2 comprising the amino acidsequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chain variableregion CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91),wherein the heavy chain variable region comprises at least 80%, at least85%, at least 90%, at least 95%, at least 97%, at least 98% identity tothe sequence of SEQ ID NO:144, and wherein the light chain variableregion comprises at least 80%, at least 85%, at least 90%, at least 95%,at least 97%, at least 98% identity to the sequence of SEQ ID NO:145.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chaincomprising a heavy chain variable region CDR1 comprising GYTFTDYYIN (SEQID NO:111), a heavy chain variable region CDR2 comprising the amino acidsequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chain variableregion CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and a light chain comprising a light chain variable region CDR1comprising the amino acid sequence RASESVDYYGNSFMY (SEQ ID NO:89), alight chain variable region CDR2 comprising the amino acid sequenceFASNLES (SEQ ID NO:90), and a light chain variable region CDR3comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91), wherein theheavy chain comprises at least 80%, at least 85%, at least 90%, at least95%, at least 97%, at least 98%, at least 99%, or 100% identity to thesequence of SEQ ID NO:156, and wherein the light chain comprises atleast 80%, at least 85%, at least 90%, at least 95%, at least 97%, atleast 98%, at least 99%, or 100% identity to the sequence of SEQ IDNO:157. In some embodiments, an ILT2/ILT4-binding agent comprises aheavy chain comprising a heavy chain variable region CDR1 comprisingGYTFTDYYIN (SEQ ID NO:111), a heavy chain variable region CDR2comprising the amino acid sequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112),and a heavy chain variable region CDR3 comprising the amino acidsequence REIYFYGTIYYYAMDY (SEQ ID NO:107), and a light chain comprisinga light chain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91), wherein the heavy chain comprises at least 95% identityto the sequence of SEQ ID NO:156, and wherein the light chain comprisesat least 95% identity to the sequence of SEQ ID NO:157. In someembodiments, an ILT2/ILT4-binding agent comprises (a) a heavy chaincomprising the amino acids of SEQ ID NO:156 and (b) a light chaincomprising a light chain variable region CDR1 comprising RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91),wherein the light chain comprises at least 80%, at least 85%, at least90%, at least 95%, at least 97%, at least 98%, at least 99%, or 100%identity to the sequence of SEQ ID NO:157. In some embodiments, anILT2/ILT4-binding agent comprises (a) a heavy chain comprising the aminoacids of SEQ ID NO:156 and (b) a light chain comprising a light chainvariable region CDR1 comprising RASESVDYYGNSFMY (SEQ ID NO:89), a lightchain variable region CDR2 comprising the amino acid sequence FASNLES(SEQ ID NO:90), and a light chain variable region CDR3 comprising theamino acid sequence QQNNEDPWT (SEQ ID NO:91). In some embodiments, anILT2/ILT4-binding agent comprises: (a) a heavy chain comprising a heavychain variable region CDR1 comprising the amino acid sequence GYTFTDYYIN(SEQ ID NO:111), a heavy chain variable region CDR2 comprising the aminoacid sequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chainvariable region CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY(SEQ ID NO:107), wherein the heavy chain comprises at least 80%, atleast 85%, at least 90%, at least 95%, at least 97%, at least 98%, atleast 99%, or 100% identity to the sequence of SEQ ID NO:156, and (b) alight chain comprising the amino acid sequence of SEQ ID NO:157. In someembodiments, an ILT2/ILT4-binding agent comprises: (a) a heavy chaincomprising a heavy chain variable region CDR1 comprising the amino acidsequence GYTFTDYYIN (SEQ ID NO:111), a heavy chain variable region CDR2comprising the amino acid sequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112),and a heavy chain variable region CDR3 comprising the amino acidsequence REIYFYGTIYYYAMDY (SEQ ID NO:107), and (b) a light chaincomprising the amino acid sequence of SEQ ID NO:157. In someembodiments, an ILT2/ILT4-binding agent is an antibody comprising aheavy chain comprising the amino acid sequence of SEQ ID NO:156 and alight chain comprising the amino acid sequence of SEQ ID NO:157.

In some embodiments, an ILT2/ILT4-binding agent comprises a heavy chainhaving at least 80%, at least 85%, at least 90%, or at least 95%identity to the amino acid sequence of SEQ ID NO:156. In someembodiments, an ILT2/ILT4-binding agent comprises a light chain havingat least 80%, at least 85%, at least 90%, or at least 95% identity tothe amino acid sequence of SEQ ID NO:157. In some embodiments, anILT2/ILT4-binding agent comprises a heavy chain having at least 80%, atleast 85%, at least 90%, or at least 95% identity to the amino acidsequence of SEQ ID NO:156 and a light chain having at least 80%, atleast 85%, at least 90%, or at least 95% identity to the amino acidsequence of SEQ ID NO:157. In some embodiments, an ILT2/ILT4-bindingagent comprises a heavy chain having at least 90% identity to the aminoacid sequence of SEQ ID NO:156. In some embodiments, anILT2/ILT4-binding agent comprises a light chain having at least 90%identity to the amino acid sequence of SEQ ID NO:157. In someembodiments, an ILT2/ILT4-binding agent comprises a heavy chain havingat least 90% identity to the amino acid sequence of SEQ ID NO:156 and alight chain having at least 90% identity to the amino acid sequence ofSEQ ID NO:157. In some embodiments, an ILT2/ILT4-binding agent comprisesa heavy chain comprising the amino acid sequence of SEQ ID NO:156. Insome embodiments, an ILT2/ILT4-binding agent comprises a light chaincomprising the amino acid sequence of SEQ ID NO:157. In someembodiments, an ILT2/ILT4-binding agent comprises a heavy chaincomprising the amino acid sequence of SEQ ID NO:156 and a light chaincomprising the amino acid sequence of SEQ ID NO:157. In someembodiments, an ILT2/ILT4-binding agent is an antibody that comprises aheavy chain of SEQ ID NO:156 and/or a light chain of SEQ ID NO:157. Insome embodiments, an ILT2/ILT4-binding agent is an antibody thatcomprises a heavy chain of SEQ ID NO:156. In some embodiments, anILT2/ILT4-binding agent is an antibody that comprises a light chain ofSEQ ID NO:157. In some embodiments, an ILT2/ILT4-binding agent is anantibody that comprises a heavy chain of SEQ ID NO:156 and a light chainof SEQ ID NO:157.

In some embodiments, the ILT2/ILT4-binding agent is antibody 73D1. Insome embodiments, the ILT2/ILT4-binding agent is antibody Hz73D1.v1.

Provided herein are agents that compete with one or more of the bindingagents described herein for binding to ILT2, ILT4, or both ILT2 andILT4. In some embodiments, an agent competes with one or more of theantibodies described herein for binding to ILT2, ILT4, or both ILT2 andILT4. In some embodiments, an agent that competes with one or more ofthe antibodies described herein is an antibody. In some embodiments, anagent binds the same epitope as one of the antibodies described herein.In some embodiments, an agent binds an epitope overlapping with anepitope bound by one of the antibodies described herein. Antibodies andantigen-binding fragments that compete with or bind the same epitope asthe antibodies described herein are expected to show similar functionalproperties.

In some embodiments, an agent competes for binding to human ILT2, ILT4,or both ILT2 and ILT4 with a reference antibody, wherein the referenceantibody comprises: (a) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence GYTFTDYYIN(SEQ ID NO:111), a heavy chain variable region CDR2 comprising the aminoacid sequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chainvariable region CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY(SEQ ID NO:107), and (b) a light chain variable region comprising alight chain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91). In some embodiments, an agent competes for binding tohuman ILT2 with a reference antibody, wherein the reference antibodycomprises: (a) a heavy chain variable region comprising a heavy chainvariable region CDR1 comprising the amino acid sequence GYTFTDYYIN (SEQID NO:111), a heavy chain variable region CDR2 comprising the amino acidsequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chain variableregion CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91).

In some embodiments, an agent competes for binding to human ILT2, ILT4,or both ILT2 and ILT4 with a reference antibody, wherein the referenceantibody comprises: (a) a heavy chain variable region comprising a heavychain variable region CDR1 comprising the amino acid sequence GYTFTDYYMN(SEQ ID NO:70), a heavy chain variable region CDR2 comprising the aminoacid sequence DFNPNNGGTTYNQKFEG (SEQ ID NO:71) or DFNPNNAGTTYNQKFEG (SEQID NO:118), and a heavy chain variable region CDR3 comprising the aminoacid sequence GRFYYGSLYSFDY (SEQ ID NO:72), and (b) a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASGNIHNYLA (SEQ ID NO:73), a light chainvariable region CDR2 comprising the amino acid sequence NAKTLAD (SEQ IDNO:74), and a light chain variable region CDR3 comprising the amino acidsequence QHFWTSIT (SEQ ID NO:75). In some embodiments, an agent competesfor binding to human ILT4 with a reference antibody, wherein thereference antibody comprises: (a) a heavy chain variable regioncomprising a heavy chain variable region CDR1 comprising the amino acidsequence GYTFTDYYMN (SEQ ID NO:70), a heavy chain variable region CDR2comprising the amino acid sequence DFNPNNGGTTYNQKFEG (SEQ ID NO:71) orDFNPNNAGTTYNQKFEG (SEQ ID NO:118), and a heavy chain variable regionCDR3 comprising the amino acid sequence GRFYYGSLYSFDY (SEQ ID NO:72),and (b) a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence RASGNIHNYLA (SEQ IDNO:73), a light chain variable region CDR2 comprising the amino acidsequence NAKTLAD (SEQ ID NO:74), and a light chain variable region CDR3comprising the amino acid sequence QHFWTSIT (SEQ ID NO:75).

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4, binding agent, or an ILT2/ILT4 binding agent) described hereincomprises an antibody in which at least one or more of the constantregions of the antibody has been modified or deleted. In someembodiments, an antibody comprises one or more modifications to one ormore of the three heavy chain constant regions (CH1, CH2 or CH3) and/orto the light chain constant region (CL). In some embodiments, anantibody comprises one or more modifications to the hinge region. Insome embodiments, the heavy chain constant region of the modifiedantibody comprises at least one human constant region. In someembodiments, the heavy chain constant region of the modified antibodycomprises more than one human constant region. In some embodiments,modifications to the constant region comprise additions, deletions, orsubstitutions of one or more amino acids in one or more regions. In someembodiments, one or more regions are partially or entirely deleted fromthe constant regions of a modified antibody. In some embodiments, theentire CH2 domain has been removed from an antibody (ΔCH2 constructs).In some embodiments, one or more regions are partially or entirelydeleted from the hinge region of a modified antibody. In someembodiments, a deleted constant region is replaced by a short amino acidspacer that provides some of the molecular flexibility typicallyimparted by the absent constant region. In some embodiments, a deletedhinge region is replaced by a short amino acid spacer that provides someof the molecular flexibility typically imparted by the absent hingeregion. In some embodiments, a modified antibody comprises a CH3 domaindirectly fused to the hinge region of the antibody. In some embodiments,a modified antibody comprises a peptide spacer inserted between thehinge region and modified CH2 and/or CH3 domains.

It is known in the art that the constant region(s) of an antibodymediates several effector functions and these effector functions canvary depending on the isotype of the antibody. For example, binding ofthe C1 component of complement to the Fc region of IgG or IgM antibodies(bound to antigen) activates the complement system. Activation ofcomplement is important in the opsonization and lysis of cell pathogens.The activation of complement also stimulates the inflammatory responseand can be involved in autoimmune hypersensitivity. In addition, the Fcregion of an antibody can bind a Fc receptor (FcR) on the surface of acell. There are a number of Fc receptors that are specific for differentclasses of antibody, including IgG (gamma receptors), IgE (epsilonreceptors), IgA (alpha receptors) and IgM (mu receptors). Binding ofantibody to Fc receptors on cell surfaces triggers a number of importantand diverse biological responses including engulfment and destruction ofantibody-coated particles, clearance of immune complexes, lysis ofantibody-coated target cells by killer cells (called antibody-dependentcell cytotoxicity or ADCC), release of inflammatory mediators, placentaltransfer, and control of immunoglobulin production.

In some embodiments, an ILT-binding agent comprises a variant Fc region.The amino acid sequences of the Fc region of human IgG1, IgG2, IgG3, andIgG4 are known to those of ordinary skill in the art (e.g., arepresentative human IgG1 region is SEQ ID NO:158). In some cases, Fcregions with amino acid variations have been identified in nativeantibodies. In some embodiments, a variant Fc region is engineered withsubstitutions at specific amino acid positions as compared to a nativeFc region. Variant Fc regions are well-known in the art and include, butare not limited to, SEQ ID NO:159, SEQ ID NO:160, SEQ ID NO:161, SEQ IDNO:162, and SEQ ID NO:163.

In some embodiments, a modified antibody provides for altered effectorfunctions that, in turn, affect the biological profile of the antibody.For example, in some embodiments, the deletion or inactivation (throughpoint mutations or other means) of a constant region reduces Fc receptorbinding of a modified antibody as it circulates. In some embodiments,constant region modifications increase the serum half-life of anantibody. In some embodiments, constant region modifications reduce theserum half-life of an antibody. In some embodiments, constant regionmodifications decrease or remove ADCC and/or complement-dependentcytotoxicity (CDC) of an antibody. In some embodiments, specific aminoacid substitutions in a human IgG1 Fc region with corresponding IgG2 orIgG4 residues reduce effector functions (e.g., ADCC and CDC) in amodified antibody. In some embodiments, a modified antibody does nothave one or more effector functions. In some embodiments, a modifiedantibody does not have any detectable effector functions(e.g.,“effectorless” antibodies). In some embodiments, a modifiedantibody has no ADCC activity and/or no CDC activity. In someembodiments, a modified antibody does not bind an Fc receptor and/orcomplement factors. In some embodiments, a modified antibody has noeffector function(s). In some embodiments, constant region modificationsincrease or enhance ADCC and/or CDC of an antibody. In some embodiments,the constant region is modified to eliminate disulfide linkages oroligosaccharide moieties. In some embodiments, the constant region ismodified to add/substitute one or more amino acids to provide one ormore cytotoxin, oligosaccharide, or carbohydrate attachment sites.

Modifications to the constant region of antibodies described herein maybe made using well-known biochemical or molecular engineeringtechniques. In some embodiments, antibody variants are prepared byintroducing appropriate nucleotide changes into the encoding DNA, and/orby synthesis of the desired antibody or polypeptide. Using theseengineering techniques to modify an antibody it may be possible todisrupt the activity or effector function provided by a specificsequence or region while substantially maintaining the structure,binding activity, and other desired characteristics of the modifiedantibody.

The present disclosure further embraces additional variants andequivalents that are substantially homologous to the recombinant,monoclonal, chimeric, humanized, and human antibodies, or antibodyfragments thereof, described herein. In some embodiments, it isdesirable to improve the binding affinity of the antibody. In someembodiments, it is desirable to modulate biological properties of theantibody, including but not limited to, specificity, thermostability,expression level, effector function(s), glycosylation, immunogenicity,and/or solubility. Those skilled in the art will appreciate that aminoacid changes may alter post-translational processes of an antibody, suchas changing the number or position of glycosylation sites or alteringmembrane anchoring characteristics.

Variations may be generated by the substitution, deletion, or insertionof one or more nucleotides into a polynucleotide encoding the antibodyor polypeptide that results in a change in an amino acid or the aminoacid sequence as compared with the native antibody or polypeptidesequence. In some embodiments, amino acid substitutions are the resultof replacing one amino acid with another amino acid having similarstructural and/or chemical properties, such as the replacement of aleucine with a serine (i.e., conservative amino acid replacements). Insome embodiments, the substitution, deletion, or insertion includes lessthan 25 amino acid substitutions, less than 20 amino acid substitutions,less than 15 amino acid substitutions, less than 10 amino acidsubstitutions, less than 5 amino acid substitutions, less than 4 aminoacid substitutions, less than 3 amino acid substitutions, or less than 2amino acid substitutions relative to the parent molecule. In someembodiments, variations in the amino acid sequence that are biologicallyuseful and/or relevant are determined by systematically makinginsertions, deletions, or substitutions in the sequence and testing theresulting variant proteins for activity as compared to the parentalantibody.

In some embodiments, variants may include addition of amino acidresidues at the amino- and/or carboxyl-terminal end of the antibody orpolypeptide. The length of additional amino acids residues may rangefrom one residue to a hundred or more residues. In some embodiments, avariant comprises an N-terminal methionyl residue. In some embodiments,the variant comprises an additional polypeptide/protein to create afusion protein. In some embodiments, a variant is engineered to bedetectable and may comprise a detectable label and/or protein (e.g., afluorescent tag, a fluorescent protein, or an enzyme).

In some embodiments, a cysteine residue not involved in maintaining theproper conformation of an antibody is substituted or deleted to modulatethe antibody's characteristics, for example, to improve oxidativestability and/or prevent aberrant disulfide crosslinking. Conversely, insome embodiments, one or more cysteine residues are added to createdisulfide bond(s) to improve stability.

In some embodiments, an antibody of the present disclosure is“deimmunized”. The deimmunization of antibodies generally consists ofintroducing specific amino acid mutations (e.g., substitutions,deletions, additions) that result in removal of T-cell epitopes (knownor predicted) without significantly reducing the binding affinity orother desired activities of the antibody.

The variant antibodies or polypeptides described herein may be generatedusing methods known in the art, including but not limited to,site-directed mutagenesis, alanine scanning mutagenesis, and PCRmutagenesis.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4-binding agent) described hereinis chemically modified. In some embodiments, an ILT-binding agent is (i)an anti-ILT2 antibody, (ii) an anti-ILT4 antibody, or (iii) ananti-ILT2/ILT4 antibody that is chemically modified by glycosylation,acetylation, pegylation, phosphorylation, amidation, derivatization byknown protecting/blocking groups, proteolytic cleavage, and/or linkageto a cellular ligand or other protein. Any of numerous chemicalmodifications may be carried out by known techniques. In someembodiments, an ILT-binding agent is an antibody fragment (e.g., scFv,Fv, Fab, F(ab′)₂, or F(ab′)), wherein the antibody fragment is attached(either directly or indirectly) to a half-life extending moietyincluding, but not limited to, polyethylene glycol (PEG), a PEG mimetic,XTEN®, serum albumin, polysialic acid,N-(2-hydroxypropyl)methacrylamide, or dextran.

The present disclosure encompasses ILT-binding agents built uponnon-immunoglobulin backbones, wherein the agents bind the same epitopeor essentially the same epitope as an anti-ILT antibody disclosedherein. In some embodiments, a non-immunoglobulin-based binding agent isan agent that competes with (i) an anti-ILT2 antibody, (ii) an anti-ILT4antibody, and/or (iii) an anti-ILT2/ILT4 antibody described herein in acompetitive binding assay. In some embodiments, alternative ILT-bindingagents comprise a scaffold protein. Generally, scaffold proteins can beassigned to one of three groups based on the architecture of theirbackbone (1) scaffolds consisting of a-helices; (2) small scaffolds withfew secondary structures or an irregular architecture of a-helices and(3-sheets; and (3) scaffolds consisting of predominantly (3-sheets.Scaffold proteins include, but are not limited to, anticalins, which arebased upon the lipocalin scaffold; adnectins, which are based on the10^(th) domain of human fibronectin type 3; affibodies, which are basedon the B-domain in the Ig-binding region of Staphylococcus aureusprotein A; darpins, which are based on ankyrin repeat domain proteins;fynomers, which are based on the SH3 domain of the human Fyn proteinkinase; affitins, which are based on Sac7d from Sulfolobusacidocaldarius; affilins, which are based on human γ-B-crystallin orhuman ubiquitin; avimers, which are based on the A-domains of membranereceptor proteins; knottins (cysteine knot miniproteins), which arebased upon a stable 30-amino acid anti-parallel β-strand protein fold;and Kunitz domain inhibitor scaffolds, which are based upon a structurethat contains three disulfide bonds and three loops.

In some embodiments, an ILT2-binding agent comprises an engineeredscaffold protein comprising a heavy chain variable region CDR1, CDR2,and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 shown inTable 1. In some embodiments, an ILT2-binding agent comprises anengineered scaffold protein comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GFSLTNYGVS (SEQ ID NO:22), aheavy chain variable region CDR2 comprising the amino acid sequenceIIWGDGSTNYHSALIS (SEQ ID NO:23), a heavy chain variable region CDR3comprising the amino acid sequence PNWDTYAIVIDF (SEQ ID NO:24), a lightchain variable region CDR1 comprising the amino acid sequenceRASQDISNFLN (SEQ ID NO:25), a light chain variable region CDR2comprising the amino acid sequence CTSKLHS (SEQ ID NO:26), and a lightchain variable region CDR3 comprising the amino acid sequence QQGNTLPPT(SEQ ID NO:27). In some embodiments, an ILT2-binding agent comprises anengineered scaffold protein comprising a heavy chain variable regionCDR1, CDR2, and CDR3 and a light chain variable region CDR1, CDR2, andCDR3 from antibody 27F9.

In some embodiments, an ILT4-binding agent comprises an engineeredscaffold protein comprising a heavy chain variable region CDR1, CDR2,and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 shown inTable 2. In some embodiments, an ILT4-binding agent comprises anengineered scaffold protein comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GYSFTGYYMH (SEQ ID NO:38), aheavy chain variable region CDR2 comprising the amino acid sequenceRVYPNNGDTSYNQKFKV (SEQ ID NO:39), a heavy chain variable region CDR3comprising the amino acid sequence GATVVESLFAY (SEQ ID NO:40), a lightchain variable region CDR1 comprising the amino acid sequenceRASESVDNYGNNFLH (SEQ ID NO:41), a light chain variable region CDR2comprising the amino acid sequence RTSNLES (SEQ ID NO:42), and a lightchain variable region CDR3 comprising the amino acid sequence QQSNEDPYT(SEQ ID NO:43). In some embodiments, an ILT4-binding agent comprises anengineered scaffold protein comprising a heavy chain variable regionCDR1, CDR2, and CDR3 and a light chain variable region CDR1, CDR2, andCDR3 from antibody 47C8.

In some embodiments, an ILT4-binding agent comprises an engineeredscaffold protein comprising a heavy chain variable region CDR1, CDR2,and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 shown inTable 3. In some embodiments, an ILT4-binding agent comprises anengineered scaffold protein comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GYTFTNYGMN (SEQ ID NO:54), aheavy chain variable region CDR2 comprising the amino acid sequenceWINTYIGEPIYADDFKG (SEQ ID NO:55), a heavy chain variable region CDR3comprising the amino acid sequence RSDYDGYAMDY (SEQ ID NO:56), a lightchain variable region CDR1 comprising the amino acid sequenceKSSQSLLYSGNQKNYLA (SEQ ID NO:57), a light chain variable region CDR2comprising the amino acid sequence WASTRES (SEQ ID NO:58), and a lightchain variable region CDR3 comprising the amino acid sequence QQHDSYPT(SEQ ID NO:59). In some embodiments, an ILT4-binding agent comprises anengineered scaffold protein comprising a heavy chain variable regionCDR1, CDR2, and CDR3 and a light chain variable region CDR1, CDR2, andCDR3 from antibody 48A5.

In some embodiments, an ILT2/ILT4-binding agent comprises an engineeredscaffold protein comprising a heavy chain variable region CDR1, CDR2,and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 shown inTable 4A or Table 4B. In some embodiments, an ILT2/ILT4-binding agentcomprises an engineered scaffold protein comprising a heavy chainvariable region CDR1 comprising the amino acid sequence GYTFTDYYMN (SEQID NO:70), a heavy chain variable region CDR2 comprising the amino acidsequence DFNPNNGGTTYNQKFEG (SEQ ID NO:71) or DFNPNNAGTTYNQKFEG (SEQ IDNO:118), a heavy chain variable region CDR3 comprising the amino acidsequence GRFYYGSLYSFDY (SEQ ID NO:72), a light chain variable regionCDR1 comprising the amino acid sequence RASGNIHNYLA (SEQ ID NO:73), alight chain variable region CDR2 comprising the amino acid sequenceNAKTLAD (SEQ ID NO:74), and a light chain variable region CDR3comprising the amino acid sequence QHFWTSIT (SEQ ID NO:75). In someembodiments, an ILT2/ILT4-binding agent comprises an engineered scaffoldprotein comprising a heavy chain variable region CDR1, CDR2, and CDR3and a light chain variable region CDR1, CDR2, and CDR3 from antibody47H6 or antibody Hz47H6.v2.

In some embodiments, an ILT2/ILT4-binding agent comprises an engineeredscaffold protein comprising a heavy chain variable region CDR1, CDR2,and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 shown inTable 5. In some embodiments, an ILT2/ILT4-binding agent comprises anengineered scaffold protein comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), aheavy chain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), a heavy chain variable region CDR3comprising the amino acid sequence DGIYYYGTMYYYAMDY (SEQ ID NO:88), alight chain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91). In some embodiments, an ILT2/ILT4-binding agentcomprises an engineered scaffold protein comprising a heavy chainvariable region CDR1, CDR2, and CDR3 and a light chain variable regionCDR1, CDR2, and CDR3 from antibody 51A1.

In some embodiments, an ILT2/ILT4-binding agent comprises an engineeredscaffold protein comprising a heavy chain variable region CDR1, CDR2,and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 shown inTable 6A or Table 6B. In some embodiments, an ILT2/ILT4-binding agentcomprises an engineered scaffold protein comprising a heavy chainvariable region CDR1 comprising the amino acid sequence GFTFNTYAMH (SEQID NO:86), a heavy chain variable region CDR2 comprising the amino acidsequence RIRSKSSNYATYYADSVKD (SEQ ID NO:87), a heavy chain variableregion CDR3 comprising the amino acid sequence DGIYYYDTMYYYAMDY (SEQ IDNO:102), a light chain variable region CDR1 comprising the amino acidsequence RASESVDYYGNSFIY (SEQ ID NO:103), a light chain variable regionCDR2 comprising the amino acid sequence FASNLES (SEQ ID NO:90), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPWT (SEQ ID NO:91). In some embodiments, an ILT2/ILT4-bindingagent comprises an engineered scaffold protein comprising a heavy chainvariable region CDR1, CDR2, and CDR3 and a light chain variable regionCDR1, CDR2, and CDR3 from antibody 64A12.

In some embodiments, an ILT2/ILT4-binding agent comprises an engineeredscaffold protein comprising a heavy chain variable region CDR1, CDR2,and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 shown inTable 7. In some embodiments, an ILT2/ILT4-binding agent comprises anengineered scaffold protein comprising a heavy chain variable regionCDR1 comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), aheavy chain variable region CDR2 comprising the amino acid sequenceNVNPNNGGTSYNQKFKG (SEQ ID NO:106), a heavy chain variable region CDR3comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ ID NO:107), alight chain variable region CDR1 comprising the amino acid sequenceRASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable region CDR2comprising the amino acid sequence FASNLES (SEQ ID NO:90), and a lightchain variable region CDR3 comprising the amino acid sequence QQNNEDPWT(SEQ ID NO:91). In some embodiments, an ILT2/ILT4-binding agentcomprises an engineered scaffold protein comprising a heavy chainvariable region CDR1, CDR2, and CDR3 and a light chain variable regionCDR1, CDR2, and CDR3 from antibody 73C4.

In some embodiments, an ILT2/ILT4-binding agent comprises an engineeredscaffold protein comprising a heavy chain variable region CDR1, CDR2,and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 shown inTable 8A or Table 8B. In some embodiments, an ILT2/ILT4-binding agentcomprises an engineered scaffold protein comprising a heavy chainvariable region CDR1 comprising the amino acid sequence GYTFTDYYIN (SEQID NO:111), a heavy chain variable region CDR2 comprising the amino acidsequence NVNPNDGGTTYNQKFKG (SEQ ID NO:112), a heavy chain variableregion CDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), a light chain variable region CDR1 comprising the amino acidsequence RASESVDYYGNSFMY (SEQ ID NO:89), a light chain variable regionCDR2 comprising the amino acid sequence FASNLES (SEQ ID NO:90), and alight chain variable region CDR3 comprising the amino acid sequenceQQNNEDPWT (SEQ ID NO:91). In some embodiments, an ILT2/ILT4-bindingagent comprises an engineered scaffold protein comprising a heavy chainvariable region CDR1, CDR2, and CDR3 and a light chain variable regionCDR1, CDR2, and CDR3 from antibody 73D1 or antibody Hz73D1.v1.

In some embodiments, a composition comprises an ILT-binding agentdescribed herein. In some embodiments, a composition comprises anILT2-binding agent described herein. In some embodiments, a compositioncomprises an ILT4-binding agent described herein. In some embodiments, acomposition comprises an ILT2/ILT4-binding agent described herein. Insome embodiments, a composition comprises an anti-ILT2 antibodydescribed herein. In some embodiments, a composition comprises amonoclonal anti-ILT2 antibody described herein. In some embodiments, acomposition comprises an anti-ILT4 antibody described herein. In someembodiments, a composition comprises a monoclonal anti-ILT4 antibodydescribed herein. In some embodiments, a composition comprises ananti-ILT2/ILT4 antibody described herein. In some embodiments, acomposition comprises a monoclonal anti-ILT2/ILT4 antibody describedherein. In some embodiments, a composition comprises an antibodyselected from the group consisting of: antibody 27F9, antibody 47C8,antibody 48A5, antibody 47H6, antibody 51A1, antibody 64A12, antibody73C4, or antibody 73D1, or humanized versions thereof.

In some embodiments, a pharmaceutical composition comprises anILT-binding agent described herein and a pharmaceutically acceptablecarrier. In some embodiments, a pharmaceutical composition comprises anILT2-binding agent described herein and a pharmaceutically acceptablecarrier. In some embodiments, a pharmaceutical composition comprises anILT4-binding agent described herein and a pharmaceutically acceptablecarrier. In some embodiments, a pharmaceutical composition comprises anILT2/ILT4-binding agent described herein and a pharmaceuticallyacceptable carrier. In some embodiments, a pharmaceutical compositioncomprises an anti-ILT2 antibody described herein and a pharmaceuticallyacceptable carrier. In some embodiments, a composition comprises amonoclonal anti-ILT2 antibody described herein and a pharmaceuticallyacceptable carrier. In some embodiments, a pharmaceutical compositioncomprises an anti-ILT4 antibody described herein and a pharmaceuticallyacceptable carrier. In some embodiments, a composition comprises amonoclonal anti-ILT4 antibody described herein and a pharmaceuticallyacceptable carrier. In some embodiments, a pharmaceutical compositioncomprises an anti-ILT2/ILT4 antibody described herein and apharmaceutically acceptable carrier. In some embodiments, a compositioncomprises a monoclonal anti-ILT2/ILT4 antibody described herein and apharmaceutically acceptable carrier. In some embodiments, apharmaceutical composition comprises an antibody selected from the groupconsisting of: antibody 27F9, antibody 47C8, antibody 48A5, antibody47H6, antibody 51A1, antibody 64A12, antibody 73C4, or antibody 73D1, orhumanized versions thereof and a pharmaceutically acceptable carrier. Insome embodiments, a pharmaceutical composition comprises antibodyHz73D1.v1 and a pharmaceutically acceptable carrier.

In some embodiments, an ILT-binding agent is isolated. In someembodiments, an ILT-binding agent is substantially pure.

Generally speaking, antigen-antibody interactions are non-covalent andreversible, formed by a combination of hydrogen bonds, hydrophobicinteractions, and electrostatic and van der Waals forces. Whendescribing the strength of an antigen-antibody complex, the termsaffinity and/or avidity are commonly used. The binding of an antibody toits antigen is a reversible process, and the affinity of the binding istypically reported as an equilibrium dissociation constant (K_(D)).K_(D) is the ratio of an antibody dissociation rate (koff) (how quicklyit dissociates from its antigen) to the antibody association rate(k_(on)) (how quickly it binds to its antigen). In some embodiments,K_(D) values are determined by measuring the k_(on) and k_(off) rates ofa specific antibody/antigen interaction and then using a ratio of thesevalues to calculate the K_(D) value. K_(D) values may be used toevaluate and rank order the strength of individual antibody/antigeninteractions. The lower the K_(D)of an antibody, the higher the affinityof the antibody for its target. In some embodiments, affinity ismeasured using SPR technology (e.g., using a Biacore system). Aviditygives a measure of the overall strength of an antibody-antigen complex.It is dependent on three major parameters: (i) affinity of the antibodyfor the target, (ii) valency of both the antibody and antigen, and (iii)structural arrangement of the parts that interact.

In some embodiments, an ILT-binding agent binds ILT2, ILT4, or both ILT2and ILT4 with a dissociation constant (K_(D)) of 1 μM or less, 100 nM orless, 40 nM or less, 20 nM or less, 10 nM or less, 1 nM or less, 0.1 nMor less, 50 pM or less, 10 pM or less, or 1 pM or less. In someembodiments, an ILT-binding agent binds ILT2, ILT4, or both ILT2 andILT4 with a K_(D) of about 20 nM or less. In some embodiments, anILT-binding agent binds ILT2, ILT4, or both ILT2 and ILT4 with a K_(D)of 10 nM or less. In some embodiments, an ILT-binding agent binds ILT2,ILT4, or both ILT2 and ILT4 with a K_(D) of 5 nM or less. In someembodiments, an ILT-binding agent binds ILT2, ILT4, or both ILT2 andILT4 with a K_(D) of 3 nM or less. In some embodiments, an ILT-bindingagent binds ILT2, ILT4, or both ILT2 and ILT4 with a K_(D) of 2 nM orless. In some embodiments, an ILT-binding agent binds ILT2, ILT4, orboth ILT2 and ILT4 with a K_(D) of 1 nM or less. In some embodiments, anILT-binding agent binds ILT2, ILT4, or both ILT2 and ILT4 with a K_(D)of 0.5 nM or less. In some embodiments, an ILT-binding agent binds ILT2,ILT4, or both ILT2 and ILT4 with a K_(D) of 0.1 nM or less. In someembodiments, an ILT-binding agent binds ILT2, ILT4, or both ILT2 andILT4 with a K_(D) of 50 pM or less. In some embodiments, an ILT-bindingagent binds ILT2, ILT4, or both ILT2 and ILT4 with a K_(D) of 25 pM orless. In some embodiments, an ILT-binding agent binds ILT2, ILT4, orboth ILT2 and ILT4 with a K_(D) of 10 pM or less. In some embodiments,an ILT-binding agent binds ILT2, ILT4, or both ILT2 and ILT4 with aK_(D) of 1 pM or less. In some embodiments, an ILT-binding agent bindsILT2, ILT4, or both ILT2 and ILT4 with a K_(D) of 0.01 nM to 2.5 nM. Insome embodiments, an ILT-binding agent binds ILT2, ILT4, or both ILT2and ILT4 with a K_(D) of 0.1 nM to 5 nM. In some embodiments, anILT-binding agent binds ILT2, ILT4, or both ILT2 and ILT4 with a K_(D)of 1 nM to 5 nM. In some embodiments, the dissociation constant of thebinding agent for ILT2 and/or ILT4 is the dissociation constantdetermined using an ILT protein (e.g., ILT2 or ILT4) immobilized on aBiacore chip and the binding agent flowed over the chip. In someembodiments, the dissociation constant of the binding agent for ILT2and/or ILT4 is the dissociation constant determined using the bindingagent captured by an anti-human IgG antibody on a Biacore chip andsoluble ILT2 or ILT4 flowed over the chip.

In some embodiments, an ILT-binding agent binds ILT2, ILT4, or both ILT2and ILT4 with a half maximal effective concentration (EC50) of 1 μM orless, 100 nM or less, 40 nM or less, 20 nM or less, 10 nM or less, 1 nMor less, or 0.1 nM or less. In some embodiments, an ILT-binding agentbinds human ILT2, ILT4, or both ILT2 and ILT4 with an EC50 of 1 μM orless, 100 nM or less, 40 nM or less, 20 nM or less, 10 nM or less, 1 nMor less, or 0.1 nM or less. In some embodiments, an ILT-binding agentbinds cyno or rhesus ILT2 with an EC50 of 40 nM or less, 20 nM or less,10 nM or less, 1 nM or less or 0.1 nM or less. In some embodiments, anILT-binding agent binds ILT2 and/or ILT4 with an EC50 of 0.1 nM to about3 nM, 0.1 nM to 2 nM, 0.1 nM to 1 nM, 0.5 nM to 3 nM, 0.5 nM to 2 nM, or0.5 nM to 1 nM.

In some embodiments, an ILT-binding agent binds human ILT2 and humanILT4 and has at least one or more of the following properties: (i) bindsrhesus ILT2/4; (ii) binds cyno ILT2/4; (iii) does not bind ILT3, ILT5,and LILRB5; (iv) does not bind LILRA2, LILRA4, LILRA5, and LILRA6; (v)is an ILT2 antagonist; (vi) is an ILT4 antagonist, (vii) inhibits ILT2activity; (viii) inhibits ILT4 activity; (ix) inhibits ILT2 signaling incells that express ILT2; (x) inhibits ILT4 signaling in cells thatexpress ILT4; (xi) inhibits binding of ILT2 to MHC I molecules; (xii)inhibits binding of ILT4 to MHC molecules; (xiii) inhibits ILT2-inducedsuppression of myeloid cells; (xiv) inhibits ILT4-induced suppression ofmyeloid cells; (xv) inhibits ILT2-induced suppression of myeloid cellactivity; (xvi) inhibits ILT4-induced suppression of myeloid cellactivity; (xvii) restores FcR activation in myeloid cells; (xviii)enhances NK cell activity; (xix) enhances CTL activity; and/or (xx)enhances macrophage phagocytosis.

The ILT-binding agents (e.g., ILT2-binding agents, ILT4-binding agents,or ILT2/ILT4-binding agents) described herein can be produced by anysuitable method known in the art. Such methods range from direct proteinsynthesis methods to constructing a DNA sequence encoding polypeptidesequences and expressing those sequences in a suitable host. In someembodiments, a DNA sequence is constructed using recombinant technologyby isolating or synthesizing a DNA sequence encoding a wild-type proteinof interest. Optionally, the sequence can be mutagenized bysite-specific mutagenesis to provide functional variants thereof. Insome embodiments, a DNA sequence encoding a polypeptide of interest isconstructed by chemical synthesis using an oligonucleotide synthesizer.Oligonucleotides can be designed based on the amino acid sequence of thedesired polypeptide and selecting those codons that are favored in thehost cell in which the recombinant polypeptide of interest will beproduced. Standard methods can be applied to synthesize a polynucleotidesequence encoding an isolated polypeptide of interest. For example, acomplete amino acid sequence can be used to construct a back-translatedgene. Further, a DNA oligomer containing a nucleotide sequence codingfor the particular isolated polypeptide can be synthesized. For example,several small oligonucleotides coding for portions of the desiredpolypeptide can be synthesized and then ligated. The individualoligonucleotides typically contain 5′ or 3′ overhangs for complementaryassembly.

Once assembled (by synthesis, site-directed mutagenesis, or anothermethod), the polynucleotide sequences encoding a particular polypeptideof interest can be inserted into an expression vector and operativelylinked to an expression control sequence appropriate for expression ofthe protein in a desired host. Proper assembly can be confirmed bynucleotide sequencing, restriction enzyme mapping, and/or expression ofa biologically active polypeptide in a suitable host.

In some embodiments, recombinant expression vectors are used to amplifyand express DNA encoding the ILT-binding agents described herein. Forexample, recombinant expression vectors can be replicable DNA constructswhich have synthetic or cDNA-derived DNA fragments encoding apolypeptide chain of an ILT-binding agent, such as an anti-ILT2/ILT4antibody, or antigen-binding fragment thereof, operatively linked tosuitable transcriptional and/or translational regulatory elementsderived from mammalian, microbial, viral, or insect genes. Atranscriptional unit generally comprises an assembly of (1) a geneticelement or elements having a regulatory role in gene expression, forexample, transcriptional promoters and/or enhancers, (2) a structural orcoding sequence that is transcribed into mRNA and translated intoprotein, and (3) appropriate transcription and translation initiationand termination sequences. Regulatory elements can include an operatorsequence to control transcription. The ability to replicate in a host,usually conferred by an origin of replication, and a selection gene tofacilitate recognition of transformants can additionally beincorporated. DNA regions are “operatively linked” when they arefunctionally related to each other. For example, DNA for a signalpeptide (secretory leader) is operatively linked to DNA for apolypeptide if it is expressed as a precursor that participates in thesecretion of the polypeptide; a promoter is operatively linked to acoding sequence if it controls the transcription of the sequence; or aribosome binding site is operatively linked to a coding sequence if itis positioned so as to permit translation. In some embodiments,structural elements intended for use in yeast expression systems includea leader sequence enabling extracellular secretion of translated proteinby a host cell. In some embodiments, in situations where recombinantprotein is expressed without a leader or transport sequence, apolypeptide may include an N-terminal methionine residue. This residuecan optionally be subsequently cleaved from the expressed recombinantprotein to provide a final product.

The choice of an expression control sequence and an expression vectorgenerally depends upon the choice of host. A wide variety of expressionhost/vector combinations can be employed. Useful expression vectors foreukaryotic hosts include, for example, vectors comprising expressioncontrol sequences from SV40, bovine papilloma virus, adenovirus, andcytomegalovirus. Useful expression vectors for bacterial hosts includeknown bacterial plasmids, such as plasmids from E. coli, including pCR1,pBR322, pMB9 and their derivatives, and wider host range plasmids, suchas M13 and other filamentous single-stranded DNA phages.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4-binding agent) of the presentdisclosure is expressed from one or more vectors. In some embodiments, aheavy chain variable region is expressed by one vector and a light chainvariable region is expressed by a second vector. In some embodiments, aheavy chain variable region and a light chain variable region areexpressed by one vector. In some embodiments, a vector encodes a heavychain variable region of an ILT-binding agent described herein. In someembodiments, a vector encodes a light chain variable region of anILT-binding agent described herein. In some embodiments, a vectorencodes a heavy chain variable region and a light chain variable regionof an ILT-binding agent described herein. In some embodiments, a heavychain polypeptide is expressed by one vector and a light chainpolypeptide is expressed by a second vector. In some embodiments, aheavy chain polypeptide and a light chain polypeptide are expressed byone vector. In some embodiments, a vector encodes a heavy chainpolypeptide of an ILT-binding agent described herein. In someembodiments, a vector encodes a light chain polypeptide of anILT-binding agent described herein. In some embodiments, a vectorencodes a heavy chain polypeptide and a light chain polypeptide of anILT-binding agent described herein.

Suitable host cells for expression of an ILT-binding agent (e.g.,ILT2-binding agents, ILT4-binding agents, or ILT2/ILT4-binding agents)or a ILT2 or ILT4 protein or fragment thereof to use as an antigen orimmunogen include prokaryotes, yeast cells, insect cells, or highereukaryotic cells under the control of appropriate promoters. Prokaryotesinclude gram-negative or gram-positive organisms, for example E. coli orBacillus. Higher eukaryotic cells include established cell lines ofmammalian origin as described herein. Cell-free translation systems mayalso be employed. Appropriate cloning vectors and expression vectors foruse with bacterial, fungal, yeast, and mammalian cellular hosts, as wellas methods of protein production, including antibody production are wellknown in the art.

Various mammalian culture systems may be used to express recombinantpolypeptides. Expression of recombinant proteins in mammalian cells maybe desirable because these proteins are generally correctly folded,appropriately modified, and biologically functional. Examples ofsuitable mammalian host cell lines include, but are not limited to,COS-7 (monkey kidney-derived), L-929 (murine fibroblast-derived), C127(murine mammary tumor-derived), 3T3 (murine fibroblast-derived), CHO(Chinese hamster ovary-derived), HeLa (human cervical cancer-derived),BHK (hamster kidney fibroblast-derived), HEK-293 (human embryonickidney-derived) cell lines and variants thereof. Mammalian expressionvectors can comprise non-transcribed elements such as an origin ofreplication, a suitable promoter and enhancer linked to the gene to beexpressed, and other 5′ or 3′ flanking non-transcribed sequences, and 5′or 3′ non-translated sequences, such as necessary ribosome bindingsites, a polyadenylation site, splice donor and acceptor sites, andtranscriptional termination sequences.

Expression of recombinant proteins in insect cell culture systems (e.g.,baculovirus) also offers a robust method for producing correctly foldedand biologically functional proteins. Baculovirus systems for productionof heterologous proteins in insect cells are well-known to those ofskill in the art.

Thus, the present disclosure provides cells comprising the ILT-bindingagents described herein. In some embodiments, the cells produce theILT-binding agents described herein. In some embodiments, the cellsproduce an antibody. In some embodiments, the cells produce an antibodythat binds human ILT2. In some embodiments, the cells produce anantibody that binds human ILT4. In some embodiments, the cells producean antibody that binds human ILT2 and ILT4. In some embodiments, thecells produce an antibody that binds human ILT2 and cyno ILT2. In someembodiments, the cells produce an anti-ILT2 antibody designated 27F9. Insome embodiments, the cells produce an anti-ILT4 antibody designated47C8. In some embodiments, the cells produce an anti-ILT4 antibodydesignated 48A5. In some embodiments, the cells produce ananti-ILT2/ILT4 antibody designated 47H6. In some embodiments, the cellsproduce a humanized anti-ILT2/ILT4 antibody designated Hz47H6.v2. Insome embodiments, the cells produce an anti-ILT2/ILT4 antibodydesignated 51A1. In some embodiments, the cells produce ananti-ILT2/ILT4 antibody designated 64A12. In some embodiments, the cellsproduce a humanized anti-ILT2/ILT4 antibody designated Hz64A12. In someembodiments, the cells produce an anti-ILT2/ILT4 antibody designated73C4. In some embodiments, the cells produce an anti-ILT2/ILT4 antibodydesignated 73D1. In some embodiments, the cells produce a humanizedanti-ILT2/ILT4 antibody designated Hz73D1.v1. In some embodiments, thecell is a prokaryotic cell. In some embodiments, the cell is aneukaryotic cell. In some embodiments, the cell is a mammalian cell. Insome embodiments, the cell is a hybridoma cell.

Proteins produced by a host cell can be purified according to anysuitable method. Standard methods include chromatography (e.g., ionexchange, affinity, and sizing column chromatography), centrifugation,differential solubility, or by any other standard technique for proteinpurification. Affinity tags such as hexahistidine (His6; SEQ ID NO:173),maltose binding domain, influenza coat sequence, andglutathione-S-transferase can be attached to the protein to allow easypurification by passage over an appropriate affinity column. Affinitychromatography methods used for purifying immunoglobulins can include,but are not limited to, Protein A, Protein G, and Protein Lchromatography. Isolated proteins can be physically characterized usingtechniques that include, but are not limited to, proteolysis, sizeexclusion chromatography (SEC), mass spectrometry (MS), nuclear magneticresonance (NMR), isoelectric focusing (IEF), high performance liquidchromatography (HPLC), and x-ray crystallography. The purity of isolatedproteins can be determined using techniques known to those of skill inthe art, including but not limited to, SDS-PAGE, SEC, capillary gelelectrophoresis, IEF, and capillary isoelectric focusing (cIEF).

In some embodiments, supernatants from expression systems that secreterecombinant protein into culture media are first concentrated using acommercially available protein concentration filter, for example, anAmicon® or Millipore Pellicon® ultrafiltration unit. Following theconcentration step, the concentrate can be applied to a suitablepurification matrix. In some embodiments, an anion exchange resin isemployed, for example, a matrix or substrate having pendantdiethylaminoethyl (DEAE) groups. The matrices can be acrylamide,agarose, dextran, cellulose, or other types commonly employed in proteinpurification. In some embodiments, a cation exchange step is employed.Suitable cation exchangers include various insoluble matrices comprisingsulfopropyl or carboxymethyl groups. In some embodiments, ahydroxyapatite media is employed, including but not limited to, ceramichydroxyapatite (CHT).

In some embodiments, one or more reverse-phase HPLC steps employinghydrophobic RP-HPLC media, e.g., silica gel having pendant methyl orother aliphatic groups, are employed to further purify a recombinantprotein. In some embodiments, hydrophobic interaction chromatography(HIC) is used to separate recombinant proteins based on theirhydrophobicity. HIC is a useful separation technique for purifyingproteins while maintaining biological activity due to the use ofconditions and matrices that operate under less denaturing conditionsthan some other techniques. Some or all of the foregoing purificationsteps, in various combinations, can be employed to provide a homogeneousrecombinant protein.

ILT-binding agents (e.g., ILT2-binding agents, ILT4-binding agents, orILT2/ILT4-binding agents) of the present disclosure may be analyzed fortheir physical/chemical properties and/or biological activities byvarious assays known in the art. In some embodiments, an anti-ILT2antibody is tested for its ability to bind ILT2 (e.g., human ILT2 and/orcyno/rhesus ILT2). In some embodiments, an anti-ILT4 antibody is testedfor its ability to bind ILT4 (e.g., human ILT4). In some embodiments, ananti-ILT2/ILT4 antibody is tested for its ability to bind ILT2 and ILT4(e.g., human ILT2, human ILT4, and cyno/rhesus ILT2). Binding assaysinclude, but are not limited to, SPR (e.g., Biacore), ELISA, and FACS.In some embodiments, an anti-ILT2 antibody is tested for its ability toinhibit, reduce, or block ILT2 binding to MHC class I antigens. In someembodiments, an anti-ILT4 antibody is tested for its ability to inhibit,reduce, or block ILT4 binding to MHC class I antigens. In someembodiments, an anti-ILT2/ILT4 antibody is tested for its ability toinhibit, reduce, or block ILT2 and ILT4 binding to MHC class I antigens.In addition, antibodies may be evaluated for solubility, stability,thermostability, viscosity, expression levels, expression quality,and/or purification efficiency.

In some embodiments, monoclonal antibodies generated against ILT2, ILT4,or ILT2 and ILT4 are grouped based upon the epitope each individualantibody recognizes, a process known as “epitope binning”. Generally,antibodies are tested in a pairwise combinatorial manner and antibodiesthat compete with each other are grouped together into bins. Forexample, in a premix binning assay, a first antibody is immobilized on asurface and a premixed solution of a second antibody and antigen isflowed over the immobilized first antibody. In tandem, the antigen isimmobilized on a surface and the two antibodies are flowed over theimmobilized antigen and compete to bind. Using these techniques,antibodies that block one another can be identified. A competitiveblocking profile is created for each antibody relative to the otherantibodies. The blocking results determine which bin each antibody isplaced in. High-throughput methods of epitope binning are known in theart and allow for screening and characterization of large numbers ofantibodies within a short period of time. Antibodies that bind similarepitopes often share similar functions and/or capabilities. Conversely,antibodies that bind different epitopes may have different functionalactivities.

In some embodiments, an epitope bin comprises at least one antibody fromthe group consisting of: 27F9, 47C8, 48A5, 47H6, 51A1, 64A12, 73C4, and73D1. In some embodiments, an epitope bin comprises at least antibodies27F9 and 73D1. In some embodiments, an epitope bin comprises at leastantibodies 27F9, 73C4, and 73D1. In some embodiments, an epitope bincomprises at least antibodies 48A5 and 47H6.

Epitope mapping is the process of identifying the binding site, orepitope on a target protein/antigen where an antibody (or other bindingagent) binds. A variety of methods are known in the art for mappingepitopes on target proteins. These methods include (i) mutagenesis,including but not limited to, shotgun mutagenesis, site-directedmutagenesis, and alanine scanning; (ii) domain or fragment scanning;(iii) peptide scanning (e.g., Pepscan technology); (iv) display methods,including but not limited to, phage display, microbial display, andribosome/mRNA display; (v) methods involving proteolysis and massspectroscopy; (vi) methods involving amide hydrogen/deuterium exchange;and (vii) structural determination, including but not limited to, x-raycrystallography and NMR.

In some embodiments, purified anti-ILT antibodies (e.g., anti-ILT2antibodies, anti-ILT4 antibodies, or anti-ILT2/ILT4 antibodies) arecharacterized by assays including, but not limited to, N-terminalsequencing, amino acid analysis, HPLC, mass spectrometry, differentialscanning fluorimetry (DSF), nanoDSF, capillary isoelectric focusing(cIEF), ion exchange chromatography, and papain digestion.

In vitro assays that characterize immune cell function include, but arenot limited to, cell activation assays (e.g., cell proliferationassays), cytotoxic T-cell (CTL) assays, T-cell suppression assays, MDSCassays, natural killer (NK) cell assays, mixed lymphocyte reaction (MLR)assays, cytokine/chemokine production assays, FcR binding assays,phagocytosis assays, and cell migration assays. In some embodiments,assays are provided for identifying anti-ILT antibodies that affect ILTactivity. “Affect or affecting ILT activity” may include, for example,inhibiting, reducing, blocking, antagonizing, suppressing, and/orinterfering with ILT2 activity, ILT4 activity, or ILT2 and ILT4activity. As ILT2 and ILT4 generally act as negativeregulator/inhibitory molecules, in some embodiments, inhibiting,reducing, blocking, antagonizing, suppressing, and/or interfering withILT2 and/or ILT4 activity results in a blockade of ILT2-induced and/orILT4-induced suppression of a biological function. Those of skill in theart may refer to this ability as “releasing the brake”, for example,anti-ILT antibodies described herein block the signaling of ILT2 and/orILT4 that would otherwise send a suppressive message. Once the “brakes”are released, the immune system is able to mount a response or astronger response to, for example, a tumor.

As described herein, ILT2 is expressed on myeloid cells, such asmonocytes, macrophages, dendritic cells (DCs), and APCs, as well as NKcells, B-cells, and CD8+ T -cells (CTLs). ILT2 activity or ILT2signaling activity includes, but is not limited to, suppression ofmyeloid cells, suppression of myeloid cell activity, suppression oftumor-associated myeloid cells, suppression of NK cells, and suppressionof cytolytic T-cells (CTLs). In some embodiments, inhibiting, reducing,blocking, antagonizing, suppressing, and/or interfering with ILT2activity results in a release of ILT2-induced suppression of anactivation signal. In some embodiments, an anti-ILT2 antibody or ananti-ILT2/ILT4 antibody inhibits ILT2 signaling. In some embodiments, ananti-ILT2 antibody or an anti-ILT2/ILT4 antibody inhibits ILT2 signalingthereby reversing an ILT2-induced suppressive effect. In someembodiments, an anti-ILT2 antibody or an anti-ILT2/ILT4 antibodyinhibits an ILT2-induced extinction signal. In some embodiments, ananti-ILT2 antibody or an anti-ILT2/ILT4 antibody increases myeloid cellactivity. In some embodiments, an anti-ILT2 antibody or ananti-ILT2/ILT4 antibody increases APC activity. In some embodiments, ananti-ILT2 antibody or an anti-ILT2/ILT4 antibody increases macrophageactivity. In some embodiments, an anti-ILT2 antibody or ananti-ILT2/ILT4 antibody increases macrophage phagocytosis. In someembodiments, an anti-ILT2 antibody or an anti-ILT2/ILT4 antibodyincreases NK cell activity. In some embodiments, an anti-ILT2 antibodyor an anti-ILT2/ILT4 antibody increases CTL activity.

ILT4 is expressed on myeloid cells, such as monocytes, macrophages,dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), andAPCs, as well as neutrophils and eosinophils. ILT4 activity or ILT4signaling activity includes, but is not limited to, suppression ofmyeloid cells, suppression of myeloid cell activity, and suppression oftumor-associated myeloid cells. In some embodiments, inhibiting,reducing, blocking, antagonizing, suppressing, and/or interfering withILT4 activity results in a release of ILT4-induced suppression of anactivation signal. In some embodiments, an anti-ILT4 antibody or ananti-ILT2/ILT4 antibody inhibits ILT4 signaling. In some embodiments, ananti-ILT4 antibody or an anti-ILT2/ILT4 antibody inhibits ILT4 signalingthereby reversing an ILT4-induced suppressive effect. In someembodiments, an anti-ILT4 antibody or an anti-ILT2/ILT4 antibodyinhibits an ILT4-induced extinction signal. In some embodiments, ananti-ILT4 antibody or an anti-ILT2/ILT4 antibody increases myeloid cellactivity. In some embodiments, an anti-ILT4 antibody or ananti-ILT2/ILT4 antibody increases macrophage activity. In someembodiments, an anti-ILT4 antibody or an anti-ILT2/ILT4 antibodydecreases MDSCs. In some embodiments, an anti-ILT4 antibody or ananti-ILT2/ILT4 antibody decreases suppression by MDSCs. In someembodiments, an anti-ILT4 antibody or an anti-ILT2/ILT4 antibody inducesa switch of MDSCs to activated macrophages.

In some embodiments, an anti-ILT2 antibody or an anti-ILT2/ILT4 antibodydisrupts the ILT2 signaling pathway. In some embodiments, an anti-ILT2antibody or an anti-ILT2/ILT4 antibody disrupts the ILT2 signalingpathway and activates myeloid cells. In some embodiments, an anti-ILT2antibody or an anti-ILT2/ILT4 antibody disrupts the ILT2 signalingpathway and activates APCs. In some embodiments, an anti-ILT2 antibodyor an anti-ILT2/ILT4 antibody disrupts the ILT2 signaling pathway andactivates dendritic cells. In some embodiments, an anti-ILT2 antibody oran anti-ILT2/ILT4 antibody disrupts the ILT2 signaling pathway andactivates primary dendritic cells. In some embodiments, an anti-ILT2antibody or an anti-ILT2/ILT4 antibody disrupts the ILT2 signalingpathway and increases NK cell activity. In some embodiments, ananti-ILT2 antibody or an anti-ILT2/ILT4 antibody disrupts the ILT2signaling pathway and increases CTL activity.

In some embodiments, an anti-ILT4 antibody or an anti-ILT2/ILT4 antibodydisrupts the ILT4 signaling pathway. In some embodiments, an anti-ILT4antibody or an anti-ILT2/ILT4 antibody disrupts the ILT4 signalingpathway and activates myeloid cells. In some embodiments, an anti-ILT4antibody or an anti-ILT2/ILT4 antibody disrupts the ILT4 signalingpathway and activates APCs. In some embodiments, an anti-ILT4 antibodyor an anti-ILT2/ILT4 antibody disrupts the ILT4 signaling pathway andactivates dendritic cells. In some embodiments, an anti-ILT4 antibody oran anti-ILT2/ILT4 antibody disrupts the ILT4 signaling pathway andactivates primary dendritic cells.

In some embodiments, an anti-ILT2/ILT4 antibody disrupts the ILT2signaling pathway and the ILT4 signaling pathway. In some embodiments,an anti-ILT2/ILT4 antibody disrupts the ILT2 signaling pathway and theILT4 signaling pathway and activates myeloid cells. In some embodiments,an anti-ILT2/ILT4 antibody disrupts the ILT2 signaling pathway and theILT4 signaling pathway and activates APCs. In some embodiments, ananti-ILT2/ILT4 antibody disrupts the ILT2 signaling pathway and the ILT4signaling pathway and activates dendritic cells. In some embodiments, ananti-ILT2/ILT4 antibody disrupts the ILT2 signaling pathway and the ILT4signaling pathway and activates primary dendritic cells. In someembodiments, an anti-ILT2/ILT4 antibody disrupts the ILT2 signalingpathway and the ILT4 signaling pathway and increases myeloid cellactivity. In some embodiments, an anti-ILT2/ILT4 antibody disrupts theILT2 signaling pathway and the ILT4 signaling pathway and increases NKcell activity. In some embodiments, an anti-ILT2/ILT4 antibody disruptsthe ILT2 signaling pathway and the ILT4 signaling pathway and increasesCTL activity. In some embodiments, an anti-ILT2/ILT4 antibody disruptsthe ILT2 signaling pathway and the ILT4 signaling pathway and decreasesMDSC activity.

In some embodiments, the terms “inhibiting”, “reducing”, “blocking”,“antagonizing”, “suppressing”, and “interfering” are relative to levelsand/or activity in the absence of treatment with the ILT-binding agent.In some embodiments, the terms “inhibiting”, “reducing”, “blocking”,“antagonizing”, “suppressing”, and “interfering” are relative to levelsand/or activity prior to treatment with the ILT-binding agent.

In some embodiments, the terms “activating”, “promoting”, “increasing”,and “enhancing” are relative to levels and/or activity in the absence oftreatment with the ILT-binding agent. In some embodiments, the terms“activating”, “promoting”, “increasing”, and “enhancing” are relative tolevels and/or activity prior to treatment with the ILT-binding agent.

In some embodiments, an anti-ILT2 antibody that inhibits ILT2 activityis antibody 27F9. In some embodiments, an anti-ILT4 antibody thatinhibits ILT4 activity is antibody 47C8. In some embodiments, ananti-ILT4 antibody that inhibits ILT4 activity is antibody 48A5. In someembodiments, an anti-ILT2/ILT4 antibody that inhibits ILT2 and ILT4activity is antibody 47H6. In some embodiments, an anti-ILT2/ILT4antibody that inhibits ILT2 and ILT4 activity is antibody Hz47H6.v2. Insome embodiments, an anti-ILT2/ILT4 antibody that inhibits ILT2 and ILT4activity is antibody 51A1. In some embodiments, an anti-ILT2/ILT4antibody that inhibits ILT2 and ILT4 activity is antibody 64A12. In someembodiments, an anti-ILT2/ILT4 antibody that inhibits ILT2 and ILT4activity is antibody Hz64A12. In some embodiments, an anti-ILT2/ILT4antibody that inhibits ILT2 and ILT4 activity is antibody 73C4. In someembodiments, an anti-ILT2/ILT4 antibody that inhibits ILT2 and ILT4activity is antibody 73D1. In some embodiments, an anti-ILT2/ILT4antibody that inhibits ILT2 and ILT4 activity is antibody Hz73D1.v1

The present disclosure also provides conjugates comprising an anti-ILT2,an anti-ILT4, or an anti-ILT2/ILT4 antibody described herein. In someembodiments, the antibody is attached to a second molecule. In someembodiments, the antibody is conjugated to a cytotoxic agent or moiety.In some embodiments, the antibody is conjugated to a cytotoxic agent toform an ADC (antibody-drug conjugate). In some embodiments, thecytotoxic agent is a chemotherapeutic agent including, but not limitedto, methotrexate, adriamycin/doxorubicin, melphalan, mitomycin C,chlorambucil, duocarmycin, daunorubicin, pyrrolobenzodiazepines (PBDs),or other intercalating agents. In some embodiments, the cytotoxic agentis a microtubule inhibitor including, but not limited to, auristatins,maytansinoids (e.g., DM1 and DM4), and tubulysins. In some embodiments,the cytotoxic agent is an enzymatically active toxin of bacterial,fungal, plant, or animal origin, or fragments thereof, including, butnot limited to, diphtheria A chain, non-binding active fragments ofdiphtheria toxin, exotoxin A chain, ricin A chain, abrin A chain,modeccin A chain, alpha-sarcin, Aleurites fordii proteins, dianthinproteins, Phytolaca americana proteins (PAPI, PAPII, and PAP-S),Momordica charantia inhibitor, curcin, crotin, Sapaonaria officinalisinhibitor, gelonin, mitogellin, restrictocin, phenomycin, enomycin, andthe tricothecenes. In some embodiments, an antibody is conjugated to oneor more small molecule toxins, such as calicheamicins, maytansinoids,trichothenes, and CC1065. A derivative of any one of these toxins may beused as long as the derivative retains the cytotoxic activity of theparent molecule.

Conjugates comprising an anti-ILT antibody (e.g., an ILT2 antibody, anILT4 antibody, or an ILT2/ILT4 antibody) described herein may be madeusing any suitable method known in the art. In some embodiments,conjugates are made using a variety of bifunctional protein-couplingagents such as N-succinimidyl-3-(2-pyridyidithiol) propionate (SPDP),iminothiolane (IT), bifunctional derivatives of imidoesters (such asdimethyl adipimidate HCl), active esters (such as disuccinimidylsuberate), aldehydes (such as glutaraldehyde), bis-azido compounds (suchas bis(p-azidobenzoyl) hexanediamine), bis-diazonium derivatives (suchas bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such astoluene 2,6-diisocyanate), and bis-active fluorine compounds (such as1,5-difluoro-2,4-dinitrobenzene).

In some embodiments, an anti-ILT antibody (e.g., an anti-ILT2 antibody,an anti-ILT4 antibody, or an anti-ILT2/ILT4 antibody) described hereinis conjugated to a detectable substance or molecule that allows theantibody to be used for diagnosis and/or detection. In some embodiments,a labeled anti-ILT antibody is used to monitor immune cells in a tumoror in the microenvironment of a tumor. In some embodiments, a labeledanti-ILT antibody is used to monitor immune cells in a tumor or in themicroenvironment of a tumor after treatment. A detectable substance caninclude but is not limited to, enzymes, such as horseradish peroxidase,alkaline phosphatase, beta-galactosidase, and acetylcholinesterase;prosthetic groups, such as biotin and flavine(s); fluorescent materials,such as, umbelliferone, fluorescein, fluorescein isothiocyanate (FITC),rhodamine, tetramethylrhodamine isothiocyanate (TRITC),dichlorotriazinylamine fluorescein, dansyl chloride, cyanine (Cy3), andphycoerythrin; bioluminescent materials, such as luciferase; radioactivematerials, such as ²¹²Bi, ¹⁴C⁵⁷Co,⁵¹Cr, ⁶⁷Cu ¹⁸F, ⁶⁸Ga, ⁶⁷Ga, ¹⁵³Gd,¹⁵⁹Gd, ⁶⁸Ge, ³H, ¹⁶⁶Ho, ¹³¹I, ¹²⁵I, ¹²³I, ¹²¹I, ¹¹⁵In, ¹¹³In, ¹¹²In,¹¹¹In, ¹⁴⁰La, ¹⁷⁷Lu, ⁵⁴Mn, ⁹⁹Mo, ³²P, ¹⁰³Pd, ^(b 149)Pm, ¹⁴²Pr, ¹⁸⁶Re,¹⁸⁸Re, ¹⁰⁵Rh, ⁹⁷Ru, ³⁵S, ⁴⁷Sc, ⁷⁵Se, ¹⁵³SM, ¹¹³Sn, ¹¹⁷Sn, ⁸⁵Sr,^(99m)Tc, ²⁰¹T, ¹³³Xe, ⁹⁰Y, ⁶⁹Yb, ¹⁷⁵Yb, ⁶⁵Zn; positron emitting metals;and magnetic metal ions.

In some embodiments, an anti-ILT antibody (e.g., an anti-ILT2 antibody,an anti-ILT4 antibody, or an anti-ILT2/ILT4 antibody) described hereinis used in an immunoassay. Immunoassays are known to those of skill inthe art and include, but are not limited to, ELISA, SPR (e.g., Biacore),FACS, and immunohistochemistry (IHC). In some embodiments, an anti-ILTantibody described herein is used on a tissue sample or a tumor sample.

An anti-ILT antibody (e.g., an anti-ILT2 antibody, an anti-ILT4antibody, or an anti-ILT2/ILT4 antibody) described herein can also beconjugated to a second antibody to form an antibody heteroconjugate.

An anti-ILT antibody (e.g., an anti-ILT2 antibody, an anti-ILT4antibody, or an anti-ILT2/ILT4 antibody) as described herein may beattached to a solid support. Such solid supports include, but are notlimited to, glass, cellulose, polyacrylamide, nylon, polystyrene,polyvinyl chloride, or polypropylene. In some embodiments, immobilizedanti-ILT antibodies are used in immunoassays. In some embodiments,immobilized anti-ILT antibodies are used in purification of the targetantigen.

III. Polynucleotides

In some embodiments, the disclosure encompasses polynucleotidescomprising polynucleotides that encode a polypeptide (e.g., anILT-binding agent) described herein. The term “polynucleotides thatencode a polypeptide” encompasses a polynucleotide that includes onlycoding sequences for the polypeptide as well as a polynucleotide thatincludes additional coding and/or non-coding sequences. Thepolynucleotides of the disclosure can be in the form of RNA or in theform of DNA. DNA includes cDNA, genomic DNA, and synthetic DNA; and canbe double-stranded or single-stranded, and if single stranded can be thecoding strand or non-coding (anti-sense) strand.

In some embodiments, a polynucleotide comprises a polynucleotideencoding a heavy chain variable region and/or a light chain variableregion of an ILT2-binding agent described herein. In some embodiments, apolynucleotide comprises a polynucleotide encoding a heavy chainvariable region of an ILT2-binding agent described herein. In someembodiments, a polynucleotide comprises a polynucleotide encoding alight chain variable region of an ILT2-binding agent described herein.In some embodiments, a polynucleotide comprises a polynucleotideencoding a heavy chain variable region of an ILT2-binding agentdescribed herein and a polynucleotide encoding a light chain variableregion of the ILT2-binding agent. In some embodiments, a polynucleotidecomprises a polynucleotide encoding a heavy chain variable region and/ora light chain variable region of an ILT4-binding agent described herein.In some embodiments, a polynucleotide comprises a polynucleotideencoding a light chain variable region of an ILT4-binding agentdescribed herein. In some embodiments, a polynucleotide comprises apolynucleotide encoding a heavy chain variable region of an ILT4-bindingagent described herein. In some embodiments, a polynucleotide comprisesa polynucleotide encoding a heavy chain variable region of anILT4-binding agent described herein and a polynucleotide encoding alight chain variable region of the ILT4-binding agent. In someembodiments, a polynucleotide comprises a polynucleotide encoding aheavy chain variable region and/or a light chain variable region of anILT2/ILT4-binding agent described herein. In some embodiments, apolynucleotide comprises a polynucleotide encoding a heavy chainvariable region of an ILT2/ILT4-binding agent described herein. In someembodiments, a polynucleotide comprises a polynucleotide encoding alight chain variable region of an ILT2/ILT4-binding agent describedherein. In some embodiments, a polynucleotide comprises a polynucleotideencoding a heavy chain variable region of an ILT2/ILT4-binding agentdescribed herein and a polynucleotide encoding a light chain variableregion of the ILT2/ILT4-binding agent.

In some embodiments, a polynucleotide comprises a polynucleotideencoding a heavy chain and/or a light chain of an ILT2-binding agentdescribed herein. In some embodiments, a polynucleotide comprises apolynucleotide encoding a heavy chain of an ILT2-binding agent describedherein. In some embodiments, a polynucleotide comprises a polynucleotideencoding a light chain of an ILT2-binding agent described herein. Insome embodiments, a polynucleotide comprises a polynucleotide encoding aheavy chain of an ILT2-binding agent described herein and apolynucleotide encoding a light chain of the ILT2-binding agent. In someembodiments, a polynucleotide comprises a polynucleotide encoding aheavy chain and/or a light chain of an ILT4-binding agent describedherein. In some embodiments, a polynucleotide comprises a polynucleotideencoding a heavy chain of an ILT4-binding agent described herein. Insome embodiments, a polynucleotide comprises a polynucleotide encoding alight chain of an ILT4-binding agent described herein. In someembodiments, a polynucleotide comprises a polynucleotide encoding aheavy chain of an ILT4-binding agent described herein and apolynucleotide encoding a light chain of the ILT4-binding agent. In someembodiments, a polynucleotide comprises a polynucleotide encoding aheavy chain and/or a light chain of an ILT2/ILT4-binding agent describedherein. In some embodiments, a polynucleotide comprises a polynucleotideencoding a heavy chain of an ILT2/ILT4-binding agent described herein.In some embodiments, a polynucleotide comprises a polynucleotideencoding a light chain of an ILT2/ILT4-binding agent described herein.In some embodiments, a polynucleotide comprises a polynucleotideencoding a heavy chain of an ILT2/ILT4-binding agent described hereinand a polynucleotide encoding a light chain of the ILT2/ILT4-bindingagent.

In some embodiments, the polynucleotide comprises a polynucleotideencoding a polypeptide comprising an amino acid sequence selected fromthe group consisting of: SEQ ID NOs:125-145. In some embodiments, thepolynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:125. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:126. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:127. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:128. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:129. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:130. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:131. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:132. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:133. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:134. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:135. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:136. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:137. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:138. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:139. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:140. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:141. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:142. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:143. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:144. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:145.

In some embodiments, the polynucleotide comprises a polynucleotideencoding a polypeptide comprising an amino acid sequence selected fromthe group consisting of: SEQ ID NOs:146-157. In some embodiments, thepolynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:146. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:147. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:148. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:149. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:150. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:151. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:152. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:153. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:154. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:155. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:156. In some embodiments,the polynucleotide comprises a polynucleotide encoding a polypeptidecomprising an amino acid sequence of SEQ ID NO:157.

In some embodiments, the polynucleotide comprises a polynucleotideencoding a polypeptide comprising more than one amino acid sequenceselected from the group consisting of: SEQ ID NOs:125-145. In someembodiments, the polynucleotide comprises a polynucleotide encoding (i)a polypeptide comprising an amino acid sequence of SEQ ID NO:125 and(ii) a polypeptide comprising an amino acid sequence of SEQ ID NO:126.In some embodiments, the polynucleotide comprises a polynucleotideencoding (i) a polypeptide comprising an amino acid sequence of SEQ IDNO:127 and (ii) a polypeptide comprising an amino acid sequence of SEQID NO:128. In some embodiments, the polynucleotide comprises apolynucleotide encoding (i) a polypeptide comprising an amino acidsequence of SEQ ID NO:129 and (ii) a polypeptide comprising an aminoacid sequence of SEQ ID NO:130. In some embodiments, the polynucleotidecomprises a polynucleotide encoding (i) a polypeptide comprising anamino acid sequence of SEQ ID NO:131 and (ii) a polypeptide comprisingan amino acid sequence of SEQ ID NO:132. In some embodiments, thepolynucleotide comprises a polynucleotide encoding (i) a polypeptidecomprising an amino acid sequence of SEQ ID NO:133 and (ii) apolypeptide comprising an amino acid sequence of SEQ ID NO:134. In someembodiments, the polynucleotide comprises a polynucleotide encoding (i)a polypeptide comprising an amino acid sequence of SEQ ID NO:135 and(ii) a polypeptide comprising an amino acid sequence of SEQ ID NO:136.In some embodiments, the polynucleotide comprises a polynucleotideencoding (i) a polypeptide comprising an amino acid sequence of SEQ IDNO:137 and (ii) a polypeptide comprising an amino acid sequence of SEQID NO:138. In some embodiments, the polynucleotide comprises apolynucleotide encoding (i) a polypeptide comprising an amino acidsequence of SEQ ID NO:139 and (ii) a polypeptide comprising an aminoacid sequence of SEQ ID NO:140. In some embodiments, the polynucleotidecomprises a polynucleotide encoding (i) a polypeptide comprising anamino acid sequence of SEQ ID NO:141 and (ii) a polypeptide comprisingan amino acid sequence of SEQ ID NO:142. In some embodiments, thepolynucleotide comprises a polynucleotide encoding (i) a polypeptidecomprising an amino acid sequence of SEQ ID NO:143 and (ii) apolypeptide comprising an amino acid sequence of SEQ ID NO:142. In someembodiments, the polynucleotide comprises a polynucleotide encoding (i)a polypeptide comprising an amino acid sequence of SEQ ID NO:144 and(ii) a polypeptide comprising an amino acid sequence of SEQ ID NO:145.

In some embodiments, the polynucleotide comprises a polynucleotideencoding a polypeptide comprising more than one amino acid sequenceselected from the group consisting of: SEQ ID NOs:146-157. In someembodiments, the polynucleotide comprises a polynucleotide encoding (i)a polypeptide comprising an amino acid sequence of SEQ ID NO:146 and(ii) a polypeptide comprising an amino acid sequence of SEQ ID NO:147.In some embodiments, the polynucleotide comprises a polynucleotideencoding (i) a polypeptide comprising an amino acid sequence of SEQ IDNO:148 and (ii) a polypeptide comprising an amino acid sequence of SEQID NO:149. In some embodiments, the polynucleotide comprises apolynucleotide encoding (i) a polypeptide comprising an amino acidsequence of SEQ ID NO:150 and (ii) a polypeptide comprising an aminoacid sequence of SEQ ID NO:151. In some embodiments, the polynucleotidecomprises a polynucleotide encoding (i) a polypeptide comprising anamino acid sequence of SEQ ID NO:152 and (ii) a polypeptide comprisingan amino acid sequence of SEQ ID NO:153. In some embodiments, thepolynucleotide comprises a polynucleotide encoding (i) a polypeptidecomprising an amino acid sequence of SEQ ID NO:154 and (ii) apolypeptide comprising an amino acid sequence of SEQ ID NO:155. In someembodiments, the polynucleotide comprises a polynucleotide encoding (i)a polypeptide comprising an amino acid sequence of SEQ ID NO:156 and(ii) a polypeptide comprising an amino acid sequence of SEQ ID NO:157.

The present disclosure also provides variants of the polynucleotidesdescribed herein, wherein a variant encodes, for example, a fragment, ananalog, and/or a derivative of a polypeptide. In some embodiments, thepresent disclosure provides a polynucleotide comprising a polynucleotidehaving a nucleotide sequence at least 80% identical, at least 85%identical, at least 90% identical, at least 95% identical, and in someembodiments, at least 96%, at least 97%, at least 98%, or at least 99%identical to a polynucleotide encoding a polypeptide described herein.

In some embodiments, a polynucleotide comprises a polynucleotide havinga nucleotide sequence at least 80% identical, at least 85% identical, atleast 90% identical, at least 95% identical, and in some embodiments, atleast 96%, at least 97%, at least 98%, or at least 99% identical to apolynucleotide encoding an amino acid sequence selected from the groupconsisting of: SEQ ID NOs:125-157. Also provided is a polynucleotidethat comprises a polynucleotide that hybridizes to a polynucleotideencoding an amino acid sequence selected from the group consisting of:SEQ ID NOs:125-157. In some embodiments, the hybridization is underconditions of high stringency as is known to those skilled in the art.

As used herein, the phrase “a polynucleotide having a nucleotidesequence at least 95% identical to a polynucleotide sequence” isintended to mean that the nucleotide sequence of the polynucleotide isidentical to a reference sequence except that the polynucleotidesequence can include up to five point mutations per each 100 nucleotidesof the reference nucleotide sequence. In other words, to obtain apolynucleotide having a nucleotide sequence at least 95% identical to areference nucleotide sequence, up to 5% of the nucleotides in thereference sequence can be deleted or substituted with anothernucleotide, or a number of nucleotides up to 5% of the total nucleotidesin the reference sequence can be inserted into the reference sequence.It is understood by those of skill in the art that an appropriatecalculation would be made for other “% identical” statements, forexample, 90% identical or 85% identical. The mutations of the referencesequence can occur at the 5′ or 3′ terminal positions of the referencenucleotide sequence or anywhere between those terminal positions,interspersed either individually among nucleotides in the referencesequence or in one or more contiguous groups within the referencesequence.

The polynucleotide variants can contain alterations in the codingregions, non-coding regions, or both. In some embodiments, apolynucleotide variant contains alterations that produce silentsubstitutions, additions, or deletions, but does not alter theproperties or activities of the encoded polypeptide. In someembodiments, a polynucleotide variant comprises silent substitutionsthat results in no change to the amino acid sequence of the polypeptide(due to the degeneracy of the genetic code). In some embodiments, apolynucleotide variant comprises one or more mutated codons comprisingone or more (e.g., 1, 2, or 3) substitutions to the codon that changethe amino acid encoded by that codon. Methods for introducing one ormore substitutions into a codon are known in the art, including but notlimited to, PCR mutagenesis and site-directed mutagenesis.Polynucleotide variants can be produced for a variety of reasons, forexample, to optimize codon expression for a particular host (e.g.,change codons in the human mRNA to those preferred by a bacterial hostsuch as E. coli). In some embodiments, a polynucleotide variantcomprises at least one silent mutation in a non-coding or a codingregion of the sequence.

In some embodiments, a polynucleotide variant is produced to modulate oralter expression (or expression levels) of the encoded polypeptide. Insome embodiments, a polynucleotide variant is produced to increaseexpression of the encoded polypeptide. In some embodiments, apolynucleotide variant is produced to decrease expression of the encodedpolypeptide. In some embodiments, a polynucleotide variant has increasedexpression of the encoded polypeptide as compared to a parentalpolynucleotide sequence. In some embodiments, a polynucleotide varianthas decreased expression of the encoded polypeptide as compared to aparental polynucleotide sequence.

In some embodiments, a polynucleotide comprises the coding sequence fora polypeptide fused in the same reading frame to a polynucleotide thataids in expression and secretion of a polypeptide from a host cell. Insome embodiments, the polynucleotide that aids in expression andsecretion is a leader sequence that functions as a secretory sequencefor controlling transport of a polypeptide. In some embodiments, thepolypeptide has a leader sequence cleaved by the host cell to form a“mature” form of the polypeptide.

In some embodiments, a polynucleotide comprises the coding sequence fora polypeptide fused in the same reading frame to a marker or tagsequence. For example, in some embodiments, a marker sequence is ahexa-histidine tag (HIS-tag; SEQ ID NO:173) that allows for efficientpurification of the polypeptide fused to the marker. In someembodiments, a marker sequence is a hemagglutinin (HA) tag derived fromthe influenza hemagglutinin protein when a mammalian host is used. Insome embodiments, the marker sequence is a FLAGTM tag. In someembodiments, a marker may be used in conjunction with other markers ortags.

In some embodiments, a polynucleotide is isolated. In some embodiments,a polynucleotide is substantially pure.

Vectors and cells comprising each and every one of the polynucleotidesdescribed herein are also provided. In some embodiments, a vectorcomprises a polynucleotide molecule encoding an ILT-binding agent (e.g.,an ILT2-binding agent, an ILT4-binding agent, or an ILT2/ILT4-bindingagent) described herein. In some embodiments, a vector comprises apolynucleotide molecule encoding a polypeptide that is part of anILT-binding agent described herein. In some embodiments, a cellcomprises a vector comprising a polynucleotide molecule encoding anILT-binding agent described herein. In some embodiments, a cellcomprises a vector comprising a polynucleotide molecule encoding apolypeptide that is part of an ILT-binding agent described herein. Insome embodiments, a cell comprises a polynucleotide molecule encoding anILT-binding agent described herein. In some embodiments, a cellcomprises one or more polynucleotides encoding an ILT-binding agentdescribed herein. In some embodiments, a cell comprises a singlepolynucleotide encoding an ILT-binding agent described herein. In someembodiments, a cell comprises a first polynucleotide encoding a heavychain variable region of an ILT-binding agent described herein and asecond polynucleotide encoding a light chain variable region of anILT-binding agent described herein. In some embodiments, a cellcomprises a polynucleotide encoding a heavy chain variable region and alight chain variable region of an ILT-binding agent described herein. Insome embodiments, a cell comprises a first polynucleotide encoding aheavy chain of an ILT-binding agent described herein and a secondpolynucleotide encoding a light chain of an ILT-binding agent describedherein. In some embodiments, a cell comprises a polynucleotide encodinga heavy chain and a light chain of an ILT-binding agent describedherein. In some embodiments, a cell comprises one or more vectorsencoding an ILT-binding agent described herein. In some embodiments, acell comprises a vector encoding an ILT-binding agent described herein.In some embodiments, a cell comprises a first vector encoding a heavychain variable region of an ILT-binding agent described herein and asecond vector encoding a light chain variable region of an ILT-bindingagent described herein. In some embodiments, a cell comprises a singlevector encoding a heavy chain variable region and a light chain variableregion of an ILT-binding agent described herein. In some embodiments, acell comprises a first vector encoding a heavy chain of an ILT-bindingagent described herein and a second vector encoding a light chain of anILT-binding agent described herein. In some embodiments, a cellcomprises a single vector encoding a heavy chain and a light chain of anILT-binding agent described herein.

IV. Methods of Making Binding Agents

The disclosure provides methods for making the ILT-binding agents (e.g.,ILT2-binding agents, ILT4-binding agents, or ILT2/ILT4-binding agents)described herein. In some embodiments, a method comprises providing acell comprising one or more polynucleotides encoding a heavy chainand/or light chain of an ILT-binding agent described herein, culturingthe cell under conditions that permit the expression of the bindingagent, and isolating the binding agent. In some embodiments, a methodfurther comprises purifying the binding agent. In some embodiments, amethod further comprises formulating the binding gent as apharmaceutical composition.

In some embodiments, a cell comprises one or more polynucleotidesencoding the heavy chain and the light chain of an ILT-binding agentdescribed herein. In some embodiments, a cell comprises a firstpolynucleotide encoding the heavy chain of an ILT-binding agent and asecond polynucleotide encoding the light chain of an ILT-binding agent.In other embodiments, a cell comprises a polynucleotide encoding theheavy chain and the light chain of an ILT-binding agent describedherein. In some embodiments, a polynucleotide encoding an ILT-bindingagent described herein is transiently transfected into a cell. In someembodiments, a polynucleotide encoding an ILT-binding agent describedherein is stably transfected into a cell.

In some embodiments, a cell comprises one or more vectors encoding theheavy chain variable region and the light chain variable region of anILT-binding agent described herein. In some embodiments, a cellcomprises a first vector encoding the heavy chain variable region of anILT-binding agent and a second vector encoding the light chain variableregion of an ILT-binding agent. In other embodiments, a cell comprises avector encoding the heavy chain variable region and the light chainvariable region of an ILT-binding agent. In some embodiments, a cellcomprises one or more vectors encoding the heavy chain and the lightchain of an ILT-binding agent described herein. In some embodiments, acell comprises a first vector encoding the heavy chain of an ILT-bindingagent and a second vector encoding the light chain of an ILT-bindingagent. In other embodiments, a cell comprises a vector encoding theheavy chain and the light chain of an ILT-binding agent describedherein.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4-binding agent) is an antibodyfragment comprising at least one antigen-binding site and the methodinvolves providing a cell comprising a polynucleotide encoding thefragment of the anti-ILT antibody, incubating the cell under conditionsthat permit the expression of the antibody fragment, and isolating theantibody fragment. In some embodiments, the cell comprises apolynucleotide encoding an antibody fragment described herein. In someembodiments, the cell comprises a vector encoding an antibody fragmentdescribed herein. In some embodiments, the method comprises purifyingthe antibody fragment. In some embodiments, the antibody fragment is aFab, Fab′, F(ab′)₂, Fv, scFv, (scFv)₂, single chain antibody, dualvariable region antibody, diabody, or nanobody.

In some embodiments, the ILT-binding agent is a scFv and the methodinvolves providing a cell comprising the scFv, incubating the cell underconditions that permit the expression of the scFv, and isolating thescFv. In some embodiments, the cell comprises a vector described hereinencoding the scFv. In some embodiments, the cell comprises apolynucleotide described herein encoding the scFv. In some embodiments,the method comprises purifying the scFv.

In some embodiments, the cell used to make an ILT-binding agent is abacterial cell. In some embodiments, the cell used to make anILT-binding agent is a yeast cell. In some embodiments, the cell used tomake an ILT-binding agent is a mammalian cell. In some embodiments, thecell used to make an ILT-binding agent is a CHO cell. In otherembodiments, the cell used to make an ILT-binding agent is a HEK-293cell.

V. Methods of use and pharmaceutical compositions

The ILT-binding agents (e.g., ILT2-binding agent, ILT4-binding agents,or ILT2/ILT4-binding agents) of the disclosure are useful in a varietyof applications including, but not limited to, therapeutic treatmentmethods, such as treatment of cancer. In some embodiments, thetherapeutic treatment methods comprise immunotherapy for cancer. In someembodiments, an ILT-binding agent described herein is useful foractivating, promoting, increasing, and/or enhancing an immune responseto cancer or cancer cells. In some embodiments, an ILT-binding agentdescribed herein is useful for activating, promoting, increasing, and/orenhancing an immune response to a tumor or tumor cells. The methods ofuse may be in vitro, ex vivo, or in vivo methods.

The present disclosure provides methods of disrupting, inhibiting, orblocking the binding of ILT2 to one or more MHC I molecules. In someembodiments, a method of disrupting, inhibiting, or blocking the bindingof ILT2 to one or more MHC I molecules comprises contacting cells withan ILT2-binding agent described herein. In some embodiments, a method ofdisrupting, inhibiting, or blocking the binding of ILT2 to one or moreMHC I molecules comprises contacting cells with an ILT2-binding agentdescribed herein, wherein the method results in disrupting, inhibiting,or blocking MHC I-induced ILT2 activity. In some embodiments, a methodof disrupting, inhibiting, or blocking the binding of ILT2 to one ormore MHC I molecules comprises contacting cells with an ILT2-bindingagent described herein, wherein the method results in disrupting,inhibiting, or blocking ILT2-induced suppression of myeloid cells. Insome embodiments, a method of disrupting, inhibiting, or blocking thebinding of ILT2 to one or more MHC I molecules comprises contactingcells with an ILT2-binding agent described herein, wherein the methodresults in disrupting, inhibiting, or blocking of ILT2-inducedsuppression of myeloid cell activity. In some embodiments, a method ofdisrupting, inhibiting, or blocking the binding of ILT2 to one or moreMHC I molecules restores FcR signaling activity in myeloid cells. Insome embodiments, the myeloid cell is a monocyte. In some embodiments,the myeloid cell is a macrophage. In some embodiments, the myeloid cellis a dendritic cell. In some embodiments, the myeloid cell is an APC. Insome embodiments, a method of disrupting, inhibiting, or blocking thebinding of ILT2 to one or more MHC I molecules comprises contactingcells with an ILT2-binding agent described herein, wherein the methodresults in increasing NK cell activity. In some embodiments, a method ofdisrupting, inhibiting, or blocking the binding of ILT2 to one or moreMHC I molecules comprises contacting cells with an ILT2-binding agentdescribed herein, wherein the method results in increasing CTL activity.In some embodiments of the methods described herein, the MHC I moleculeis a classical MHC I molecule. In some embodiments of the methodsdescribed herein, the MHC I molecule is a non-classical MHC I molecule.In some embodiments of the methods described herein, the MHC I moleculeis HLA-A, HLA-B, HLA-C, HLA-E, and/or HLA-G.

The present disclosure provides methods of disrupting, inhibiting, orblocking the binding of ILT4 to one or more MHC I molecules. In someembodiments, a method of disrupting, inhibiting, or blocking the bindingof ILT4 to one or more MHC I molecules comprises contacting cells withan ILT4-binding agent described herein. In some embodiments, a method ofdisrupting, inhibiting, or blocking the binding of ILT4 to one or moreMHC I molecules comprises contacting cells with an ILT4-binding agentdescribed herein, wherein the method results in disrupting, inhibiting,or blocking MHC I-induced ILT4 activity. In some embodiments, a methodof disrupting, inhibiting, or blocking the binding of ILT4 to one ormore MHC I molecules comprises contacting cells with an ILT4-bindingagent described herein, wherein the method results in disrupting,inhibiting, or blocking ILT4-induced suppression of myeloid cells. Insome embodiments, a method of disrupting, inhibiting, or blocking thebinding of ILT2 to one or more MHC I molecules comprises contactingcells with an ILT4-binding agent described herein, wherein the methodresults in disrupting, inhibiting, or blocking of ILT4-inducedsuppression of myeloid cell activity. In some embodiments, a method ofdisrupting, inhibiting, or blocking the binding of ILT4 to one or moreMHC I molecules restores FcR signaling activity in myeloid cells. Insome embodiments, the myeloid cell is a monocyte. In some embodiments,the myeloid cell is a macrophage. In some embodiments, the myeloid cellis a dendritic cell. In some embodiments, the myeloid cell is an APC. Insome embodiments of the methods described herein, the MHC I molecule isa classical MHC I molecule. In some embodiments of the methods describedherein, the MHC I molecule is a non-classical MHC I molecule. In someembodiments of the methods described herein, the MHC I molecule isHLA-A, HLA-B, HLA-C, HLA-E, and/or HLA-G.

The present disclosure provides methods of disrupting, inhibiting, orblocking the binding of ILT2 and ILT4 to one or more MHC I molecules. Insome embodiments, a method of disrupting, inhibiting, or blocking thebinding of ILT2 and ILT4 to one or more MHC I molecules comprisescontacting cells with an ILT2/ILT4-binding agent described herein. Insome embodiments, a method of disrupting, inhibiting, or blocking thebinding of ILT2 and ILT4 to one or more MHC I molecules comprisescontacting cells with an ILT2/ILT4-binding agent described herein,wherein the method results in disrupting, inhibiting, or blocking MHCI-induced ILT2 and/or ILT4 activity. In some embodiments, a method ofdisrupting, inhibiting, or blocking the binding of ILT2 and ILT4 to oneor more MHC I molecules comprises contacting cells with anILT2/ILT4-binding agent described herein, wherein the method results indisrupting, inhibiting, or blocking ILT2-induced and/or ILT4-inducedsuppression of myeloid cells. In some embodiments, a method ofdisrupting, inhibiting, or blocking the binding of ILT2 and ILT4 to oneor more MHC I molecules comprises contacting cells with anILT2/ILT4-binding agent described herein, wherein the method results indisrupting, inhibiting, or blocking of ILT2-induced and/or ILT4-inducedsuppression of myeloid cell activity. In some embodiments, a method ofdisrupting, inhibiting, or blocking the binding of ILT2 and ILT4 to oneor more MHC I molecules restores FcR signaling activity in myeloidcells. In some embodiments, the myeloid cell is a monocyte. In someembodiments, the myeloid cell is a macrophage. In some embodiments, themyeloid cell is a dendritic cell. In some embodiments, the myeloid cellis an APC. In some embodiments, a method of disrupting, inhibiting, orblocking the binding of ILT2 and ILT4 to one or more MHC I moleculescomprises contacting cells with an ILT2/ILT4-binding agent describedherein, wherein the method results in increasing NK cell activity. Insome embodiments, a method of disrupting, inhibiting, or blocking thebinding of ILT2 and ILT4 to one or more MHC I molecules comprisescontacting cells with an ILT2/ILT4-binding agent described herein,wherein the method results in increasing CTL activity.

The present disclosure provides methods of disrupting, inhibiting, orblocking the binding of ILT2 and/or ILT4 to MHC I molecules in asubject. In some embodiments, a method of disrupting, inhibiting, orblocking the binding of ILT2 and/or ILT4 to MHC I molecules in asubject, comprises administering to the subject an effective amount ofan ILT2/ILT4-binding agent described herein. In some embodiments, amethod of disrupting, inhibiting, or blocking MHC I-induced ILT2 and/orILT4 activity in a subject comprises administering to the subject aneffective amount of an ILT2/ILT4-binding agent described herein. In someembodiments, a method of disrupting, inhibiting, or blockingILT2-induced and/or ILT4-induced suppression of myeloid cells in asubject comprises administering to the subject an effective amount of anILT2/ILT4-binding agent described herein. In some embodiments, a methodof disrupting, inhibiting, or blocking ILT2-induced and/or ILT4-inducedsuppression of myeloid cell activity in a subject comprisesadministering to the subject an effective amount of an ILT2/ILT4-bindingagent described herein. In some embodiments, a method of disrupting,inhibiting, or blocking ILT2-induced and/or ILT4-induced suppression ofantigen-presenting cell activity in a subject restores FcR activity inmyeloid cells. In some embodiments, the myeloid cell is a monocyte. Insome embodiments, the myeloid cell is a macrophage. In some embodiments,the myeloid cell is a dendritic cell. In some embodiments, the myeloidcell is an APC.

The present disclosure provides methods for activating an immuneresponse in a subject using an ILT2/ILT4-binding agent described herein.In some embodiments, the disclosure provides methods for promoting animmune response in a subject using an ILT2/ILT4-binding agent describedherein. In some embodiments, the disclosure provides methods forincreasing an immune response in a subject using an ILT2/ILT4-bindingagent described herein. In some embodiments, the disclosure providesmethods for enhancing an immune response in a subject using anILT2/ILT4-binding agent described herein. In some embodiments, theactivating, promoting, increasing, and/or enhancing of an immuneresponse comprises stimulating myeloid cells. In some embodiments, theactivating, promoting, increasing, and/or enhancing of an immuneresponse comprises stimulating monocytes. In some embodiments, theactivating, promoting, increasing, and/or enhancing of an immuneresponse comprises stimulating macrophages. In some embodiments, theactivating, promoting, increasing, and/or enhancing of an immuneresponse comprises stimulating dendritic cells. In some embodiments, theactivating, promoting, increasing, and/or enhancing of an immuneresponse comprises stimulating APCs. In some embodiments, theactivating, promoting, increasing, and/or enhancing of an immuneresponse comprises increasing cell-mediated immunity. In someembodiments, the activating, promoting, increasing, and/or enhancing ofan immune response comprises increasing effector T-cell activity. Insome embodiments, the activating, promoting, increasing, and/orenhancing of an immune response comprises increasing CTL activity. Insome embodiments, the activating, promoting, increasing, and/orenhancing of an immune response comprises increasing NK cell activity.In some embodiments, the activating, promoting, increasing, and/orenhancing of an immune response comprises enhancing NK cell activity. Insome embodiments, the activating, promoting, increasing, and/orenhancing of an immune response comprises inhibiting or decreasing thesuppressive activity of Tregs. In some embodiments, the activating,promoting, increasing, and/or enhancing of an immune response comprisesinhibiting or decreasing the suppressive activity of MDSCs. In someembodiments, the immune response is a result of antigenic stimulation.In some embodiments, the antigenic stimulation is a tumor cell. In someembodiments, the antigenic stimulation is cancer.

The disclosure also provides methods of disrupting and/or inhibitingILT2 and/or ILT4 signaling in a cell comprising contacting the cell withan effective amount of an ILT2-binding agent, an ILT4-binding agent, oran ILT2/ILT4-binding agent described herein. In some embodiments, themethod of disrupting and/or inhibiting ILT2 signaling in a cellcomprises contacting the cell with an effective amount of antibody 27F9,antibody 47H6, antibody 51A1, antibody 64A12, antibody 73C4, or antibody73D1, or a humanized version thereof. In some embodiments, the method ofdisrupting and/or inhibiting ILT4 signaling in a cell comprisescontacting the cell with an effective amount of antibody 47C8, antibody48A5, antibody 47H6, antibody 51A1, antibody 64A12, antibody 73C4, orantibody 73D1, or a humanized version thereof. In some embodiments, themethod of disrupting and/or inhibiting ILT2 signaling and ILT4 signalingin a cell comprises contacting the cell with an effective amount ofantibody 47H6, antibody 51A1, antibody 64A12, antibody 73C4, or antibody73D1, or a humanized version thereof. In some embodiments, the method ofdisrupting and/or inhibiting ILT2 signaling and ILT4 in a cell comprisescontacting the cell with an effective amount of antibody Hz47H6.v2. Insome embodiments, the method of disrupting and/or inhibiting ILT2signaling and ILT4 in a cell comprises contacting the cell with aneffective amount of antibody Hz64A12. In some embodiments, the method ofdisrupting and/or inhibiting ILT2 signaling and ILT4 in a cell comprisescontacting the cell with an effective amount of antibody Hz73D1.v1. Insome embodiments, the disclosure provides use of an ILT2-binding agentdescribed herein in the manufacture or preparation of a medicament fordisrupting and/or inhibiting ILT2 signaling in a cell. In someembodiments, the disclosure provides use of an ILT4-binding agentdescribed herein in the manufacture or preparation of a medicament fordisrupting and/or inhibiting ILT4 signaling in a cell. In someembodiments, the disclosure provides use of an ILT2/ILT4-binding agentdescribed herein in the manufacture or preparation of a medicament fordisrupting and/or inhibiting ILT2 signaling and ILT4 signaling in acell. In some embodiments, the cell is a myeloid cell. In someembodiments, the cell is a monocyte. In some embodiments, the cell is amacrophage. In some embodiments, the cell is a dendritic cell. In someembodiments, the cell is an antigen-presenting cell. In someembodiments, the cells is a NK cell. In some embodiments, the cell is aCTL. In some embodiments, the method is an in vivo method wherein thestep of contacting the cell with the agent comprises administering atherapeutically effective amount of an ILT-binding agent to a subject.In some embodiments, the method is an in vitro or ex vivo method.

The present disclosure also provides methods for inhibiting growth of atumor using an ILT2-binding agent, an ILT4-binding agent, or anILT2/ILT4-binding agent described herein. In some embodiments, themethod of inhibiting growth of a tumor comprises using an ILT2-bindingagent described herein. In some embodiments, the method of inhibitinggrowth of a tumor comprises using antibody 27F9 or a humanized versionthereof. In some embodiments, the method of inhibiting growth of a tumorcomprises using an ILT4-binding agent described herein. In someembodiments, the method of inhibiting growth of a tumor comprises usingantibody 47C8 or antibody 48A5, or a humanized version thereof. In someembodiments, the method of inhibiting growth of a tumor comprises usingan ILT2/ILT4-binding agent described herein. In some embodiments, themethod of inhibiting growth of a tumor comprises using antibody 47H6,antibody 51A1, antibody 64A12, antibody 73C4, or antibody 73D1, orhumanized versions thereof. In some embodiments, the method ofinhibiting growth of a tumor comprises using antibody Hz47H6.v2. In someembodiments, the method of inhibiting growth of a tumor comprises usingantibody Hz64A12. In some embodiments, the method of inhibiting growthof a tumor comprises using antibody Hz73D1.v1. In some embodiments, themethod of inhibiting growth of a tumor comprises contacting a cellmixture with an ILT-binding agent in vitro. For example, an immortalizedcell line or a cancer cell line mixed with immune cells (e.g., a myeloidcell) is cultured in medium to which is added a test agent that bindsILT2 and/or ILT4. In some embodiments, tumor cells are isolated from apatient sample such as, for example, a tissue biopsy, pleural effusion,or blood sample, mixed with immune cells (e.g., myeloid cells), andcultured in medium to which is added a test agent that binds ILT2 and/orILT4. In some embodiments, the disclosure provides use of anILT2-binding agent described herein in the manufacture or preparation ofa medicament for inhibiting growth of a tumor or a tumor cell. In someembodiments, the disclosure provides use of an ILT4-binding agentdescribed herein in the manufacture or preparation of a medicament forinhibiting growth of a tumor or a tumor cell. In some embodiments, thedisclosure provides use of an ILT2/ILT4-binding agent described hereinin the manufacture or preparation of a medicament for inhibiting growthof a tumor or a tumor cell. In some embodiments, an ILT2-binding agentincreases, promotes, and/or enhances the activity of effector immunecells. In some embodiments, an ILT2-binding agent inhibits tumor cellgrowth by increasing, promoting, and/or enhancing the activity ofeffector immune cells. In some embodiments, an ILT4-binding agentincreases, promotes, and/or enhances the activity of effector immunecells. In some embodiments, an ILT4-binding agent inhibits tumor cellgrowth by increasing, promoting, and/or enhancing the activity ofeffector immune cells. In some embodiments, an ILT2/ILT4-binding agentincreases, promotes, and/or enhances the activity of effector immunecells. In some embodiments, an ILT2/ILT4-binding agent inhibits tumorcell growth by increasing, promoting, and/or enhancing the activity ofeffector immune cells.

In some embodiments, a method of inhibiting tumor growth comprisescontacting the tumor and/or tumor microenvironment with an ILT-bindingagent (e.g., an ILT2-binding agent, an ILT4-binding agent, or anILT2/ILT4-binding agent) described herein in vivo. In some embodiments,contacting a tumor and/or tumor microenvironment with an ILT-bindingagent described herein is undertaken in an animal model. For example, atest agent (e.g., an ILT2/ILT4-binding agent) may be administered tomice that have tumors. In some embodiments, an ILT2/ILT4-binding agentincreases, promotes, and/or enhances the activity of immune cells in themice. In some embodiments, an ILT2/ILT4-binding agent inhibits tumorgrowth. In some embodiments, an ILT2/ILT4-binding agent causes a tumorto regress. In some embodiments, an ILT2/ILT4-binding agent isadministered at the same time or shortly after introduction of tumorcells into the animal to prevent tumor growth (“preventative model”). Insome embodiments, an ILT2/ILT4-binding agent is administered aftertumors have grown to a specified size or have become “established” fortreatment (“therapeutic model”). In some embodiments, anILT2/ILT4-binding agent is administered to a transgenic animal (e.g., atransgenic mouse) that expresses human ILT2 and/or ILT4, wherein thetransgenic animal has a tumor derived from human cells.

In some embodiments, a method of inhibiting tumor growth comprisesadministering to a subject a therapeutically effective amount of anILT-binding agent (e.g., an ILT2-binding agent, an ILT4-binding agent,or an ILT2/ILT4-binding agent) described herein. In some embodiments, amethod of inhibiting tumor growth comprises administering to a subject atherapeutically effective amount of an ILT2/ILT4-binding agent describedherein. In some embodiments, a method of increasing or enhancing animmune response to a tumor or tumor cells in a subject comprisesadministering to the subject a therapeutically effective amount of anILT2/ILT4-binding agent described herein. In some embodiments, a methodof activating or enhancing a persistent or long-term immune response toa tumor or tumor cells in a subject comprises administering to thesubject a therapeutically effective amount of an ILT2/ILT4-binding agentdescribed herein. In some embodiments, a method of inhibiting tumorrelapse or tumor regrowth in a subject comprises administering to thesubject a therapeutically effective amount of an ILT2/ILT4-binding agentdescribed herein. In some embodiments, a method of inducing a persistentor long-term immunity that inhibits tumor relapse or tumor regrowth in asubject comprises administering to the subject a therapeuticallyeffective amount of an ILT2/ILT4-binding agent described herein. In someembodiments of the methods described herein, the tumor is a solid tumor.In some embodiments, the tumor is a pancreatic tumor, a breast tumor, alung tumor, a non-small cell lung tumor, a head and neck tumor, acolorectal tumor, a prostate tumor, a skin tumor, a melanoma tumor, astomach tumor, a gastric tumor, an intestinal tumor, an ovarian tumor, acervical tumor, an uterine tumor, an endometrial tumor, a bladder tumor,a brain tumor, an esophageal tumor, a liver tumor, a kidney tumor, arenal cell carcinoma, or a testicular tumor. In some embodiments, thetumor is a pancreatic tumor. In some embodiments, the tumor is anon-small cell lung tumor. In some embodiments, the tumor is a renalcell carcinoma (RCC). In some embodiments, the subject has a tumor orthe subject had a tumor that was at least partially removed. In someembodiments of the methods described herein, the subject is a human.

In some embodiments, the disclosure provides use of an ILT2-bindingagent, an ILT4-binding agent, or an ILT2/ILT4-binding agent describedherein in the manufacture or preparation of a medicament for inhibitinggrowth of a tumor or tumor cell. In some embodiments, the method ofinhibiting growth of a tumor comprises administering to a subject atherapeutically effective amount of antibody 27F9, antibody 47C8,antibody 48A5, antibody 47H6, antibody 51A1, antibody 64A12, antibody73C4, or antibody 73D1, or humanized versions thereof. In someembodiments, the method of inhibiting growth of a tumor comprisesadministering to a subject a therapeutically effective amount ofantibody Hz47H6.v2. In some embodiments, the method of inhibiting growthof a tumor comprises administering to a subject a therapeuticallyeffective amount of antibody Hz64A12. In some embodiments, the method ofinhibiting growth of a tumor comprises administering to a subject atherapeutically effective amount of antibody Hz73D1.v1. In someembodiments of the methods described herein, the subject is a human.

The present disclosure provides methods of treating cancer. In someembodiments, a method of treating cancer comprises administering to asubject a therapeutically effective amount of an ILT2-binding agentdescribed herein. In some embodiments, a method of treating cancercomprises administering to a subject a therapeutically effective amountof an ILT4-binding agent described herein. In some embodiments, a methodof treating cancer comprises administering to a subject atherapeutically effective amount of an ILT2/ILT4-binding agent describedherein. In some embodiments, an ILT2/ILT4-binding agent binds ILT2and/or ILT4 and inhibits or reduces growth of the cancer. In someembodiments, an ILT2/ILT4-binding agent binds human ILT2-expressingcells and/or ILT4-expressing cells, enhances an immune response to acancer, and inhibits or reduces growth of the cancer. In someembodiments, an ILT2/ILT4-binding agent binds human ILT2-expressingcells and/or ILT4-expressing cells, activates myeloid cells, enhances animmune response to a cancer, and inhibits or reduces growth of thecancer. In some embodiments, the subject is a human. In someembodiments, the subject has a cancerous tumor. In some embodiments, thesubject has had the cancer at least partially removed.

In some embodiments, the disclosure provides use of an ILT2-bindingagent described herein in the manufacture or preparation of a medicamentfor the treatment of cancer. In some embodiments, the disclosureprovides use of an ILT4-binding agent described herein in themanufacture or preparation of a medicament for the treatment of cancer.In some embodiments, the disclosure provides use of an ILT2/ILT4-bindingagent described herein in the manufacture or preparation of a medicamentfor the treatment of cancer.

In some embodiments of the methods described herein, the cancer ispancreatic cancer, breast cancer, lung cancer, non-small cell lungcancer (NSCLC), head and neck cancer, colorectal cancer, prostatecancer, skin cancer, melanoma, stomach cancer, gastric cancer,intestinal cancer, ovarian cancer, cervical cancer, uterine cancer,endometrial cancer, bladder cancer, brain cancer, esophageal cancer,liver cancer, kidney cancer, renal cell carcinoma (RCC), or testicularcancer. In some embodiments, the cancer is pancreatic cancer. In someembodiments, the cancer is breast cancer. In some embodiments, thecancer is non-small cell lung cancer. In some embodiments, the cancer isrenal cell carcinoma.

In some embodiments, a method for treating cancer in a subject comprisesadministering to the subject a therapeutically effective amount ofantibody 27F9 or a humanized version thereof. In some embodiments, amethod for treating cancer in a subject comprises administering to thesubject a therapeutically effective amount of antibody 47C8 or antibody48A5, or a humanized version thereof. In some embodiments, a method fortreating cancer in a subject comprises administering to the subject atherapeutically effective amount of antibody 47H6, antibody 51A1,antibody 64A12, antibody 73C4, or antibody 73D1, or a humanized versionthereof. In some embodiments, a method for treating cancer in a subjectcomprises administering to the subject a therapeutically effectiveamount of antibody Hz47H6.v2. In some embodiments, a method for treatingcancer in a subject comprises administering to the subject atherapeutically effective amount of antibody Hz64A12. In someembodiments, a method for treating cancer in a subject comprisesadministering to the subject a therapeutically effective amount ofantibody Hz73D1.v1.

In some embodiments, the disclosure provides methods of activatingmyeloid cells in the tumor microenvironment. In some embodiments, amethod of activating myeloid cells in the tumor microenvironment in asubject with a tumor comprises administering to the subject atherapeutically effective amount of an ILT2-binding agent, anILT4-binding agent, or an ILT2/ILT4-binding agent described herein. Insome embodiments, a method of activating myeloid cells in the tumormicroenvironment in a subject with a tumor comprises administering tothe subject a therapeutically effective amount of an ILT2/ILT4-bindingagent described herein. In some embodiments, the myeloid cells areprimary dendritic cells. In some embodiments, the myeloid cells aremonocytes. In some embodiments, the myeloid cells are macrophages. Insome embodiments, the myeloid cells are APCs.

In some embodiments, the disclosure provides methods of activating NKcells in the tumor microenvironment. In some embodiments, a method ofactivating NK cells in the tumor microenvironment in a subject with atumor comprises administering to the subject a therapeutically effectiveamount of an ILT2-binding agent or an ILT2/ILT4-binding agent describedherein. In some embodiments, a method of activating NK cells in thetumor microenvironment in a subject with a tumor comprises administeringto the subject a therapeutically effective amount of an ILT2-bindingagent described herein. In some embodiments, a method of activating NKcells in the tumor microenvironment in a subject with a tumor comprisesadministering to the subject a therapeutically effective amount of anILT2/ILT4-binding agent described herein.

In some embodiments, the disclosure provides methods of activating CTLsin the tumor microenvironment. In some embodiments, a method ofactivating CTLs in the tumor microenvironment in a subject with a tumorcomprises administering to the subject a therapeutically effectiveamount of an ILT2-binding agent or an ILT2/ILT4-binding agent describedherein. In some embodiments, a method of activating CTLs in the tumormicroenvironment in a subject with a tumor comprises administering tothe subject a therapeutically effective amount of an ILT2-binding agentdescribed herein. In some embodiments, a method of activating CTLs inthe tumor microenvironment in a subject with a tumor comprisesadministering to the subject a therapeutically effective amount of anILT2/ILT4-binding agent described herein.

In some embodiments of the methods described herein, an ILT2-bindingagent comprises a heavy chain variable region CDR1, CDR2, and CDR3 and alight chain variable region CDR1, CDR2, and CDR3 of antibody 27F9.

In some embodiments of the method described herein, an ILT2-bindingagent is an anti-ILT2 antibody. In some embodiments of the methodsdescribed herein, the anti-ILT2 antibody comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GFSLTNYGVS (SEQ ID NO:22), a heavy chainvariable region CDR2 comprising the amino acid sequence IIWGDGSTNYHSALIS(SEQ ID NO:23), and a heavy chain variable region CDR3 comprising theamino acid sequence PNWDTYAMIDF (SEQ ID NO:24), and (b) a light chainvariable region comprising a light chain variable region CDR1 comprisingthe amino acid sequence RASQDISNFLN (SEQ ID NO:25), a light chainvariable region CDR2 comprising the amino acid sequence CTSKLHS (SEQ IDNO:26), and a light chain variable region CDR3 comprising the amino acidsequence QQGNTLPPT (SEQ ID NO:27). In some embodiments of the methodsdescribed herein, the anti-ILT2 antibody comprises: (a) a heavy chainvariable region of SEQ ID NO:125 and (b) a light chain variable regionof SEQ ID NO:126. In some embodiments of the methods described herein,the anti-ILT2 antibody is antibody 27F9. In some embodiments of themethods described herein, the anti-ILT2 antibody is a humanized versionof 27F9.

In some embodiments of the methods described herein, the ILT4-bindingagent comprises a heavy chain variable region CDR1, CDR2, and CDR3 and alight chain variable region CDR1, CDR2, and CDR3 of antibody 47C8.

In some embodiments of the method described herein, an ILT4-bindingagent is an anti-ILT4 antibody. In some embodiments of the methodsdescribed herein, the anti-ILT4 antibody comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYSFTGYYMH (SEQ ID NO:38), a heavy chainvariable region CDR2 comprising the amino acid sequenceRVYPNNGDTSYNQKFKV (SEQ ID NO:39), and a heavy chain variable region CDR3comprising the amino acid sequence GATVVESLFAY (SEQ ID NO:40), and (b) alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASESVDNYGNNFLH (SEQ ID NO:41),a light chain variable region CDR2 comprising the amino acid sequenceRTSNLES (SEQ ID NO:42), and a light chain variable region CDR3comprising the amino acid sequence QQSNEDPYT (SEQ ID NO:43. In someembodiments of the methods described herein, the anti-ILT4 antibodycomprises: (a) a heavy chain variable region of SEQ ID NO:127 and (b) alight chain variable region of SEQ ID NO:128. In some embodiments of themethods described herein, the anti-ILT4 antibody is antibody 47C8. Insome embodiments of the methods described herein, the anti-ILT4 antibodyis a humanized version of antibody 47C8.

In some embodiments of the methods described herein, the ILT4-bindingagent comprises a heavy chain variable region CDR1, CDR2, and CDR3 and alight chain variable region CDR1, CDR2, and CDR3 of antibody 48A5.

In some embodiments of the method described herein, an ILT4-bindingagent is an anti-ILT4 antibody. In some embodiments of the methodsdescribed herein, the anti-ILT4 antibody comprises: (a) a heavy chainvariable region comprising a heavy chain variable region CDR1 comprisingthe amino acid sequence GYTFTNYGMN (SEQ ID NO:54), a heavy chainvariable region CDR2 comprising the amino acid sequenceWINTYIGEPIYADDFKG (SEQ ID NO:55), and a heavy chain variable region CDR3comprising the amino acid sequence RSDYDGYAMDY (SEQ ID NO:56), and (b) alight chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence KSSQSLLYSGNQKNYLA (SEQ IDNO:57), a light chain variable region CDR2 comprising the amino acidsequence WASTRES (SEQ ID NO:58), and a light chain variable region CDR3comprising the amino acid sequence QQHDSYPT (SEQ ID NO:59). In someembodiments of the methods described herein, the anti-ILT4 antibodycomprises: (a) a heavy chain variable region of SEQ ID NO:129 and (b) alight chain variable region of SEQ ID NO:130. In some embodiments of themethods described herein, the anti-ILT4 antibody is antibody 48A5. Insome embodiments of the methods described herein, the anti-ILT4 antibodyis a humanized version of antibody 48A5.

In some embodiments of the methods described herein, theILT2/ILT4-binding agent comprises a heavy chain variable region CDR1,CDR2, and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 ofantibody 47H6 or antibody Hz47H6.v2.

In some embodiments of the method described herein, an ILT2/ILT4-bindingagent is an anti-ILT2/ILT4 antibody. In some embodiments of the methodsdescribed herein, the anti-ILT2/ILT4 antibody comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavychain variable region CDR2 comprising the amino acid sequenceDFNPNNGGTTYNQKFEG (SEQ ID NO:71) or DFNPNNAGTTYNQKFEG (SEQ ID NO:118),and a heavy chain variable region CDR3 comprising the amino acidsequence GRFYYGSLYSFDY (SEQ ID NO:72), and (b) a light chain variableregion comprising a light chain variable region CDR1 comprising theamino acid sequence RASGNIHNYLA (SEQ ID NO:73), a light chain variableregion CDR2 comprising the amino acid sequence NAKTLAD (SEQ ID NO:74),and a light chain variable region CDR3 comprising the amino acidsequence QHFWTSIT (SEQ ID NO:75). In some embodiments of the methodsdescribed herein, the anti-ILT2/ILT4 antibody comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavychain variable region CDR2 comprising the amino acid sequenceDFNPNNGGTTYNQKFEG (SEQ ID NO:71), and a heavy chain variable region CDR3comprising the amino acid sequence GRFYYGSLYSFDY (SEQ ID NO:72), and (b)a light chain variable region comprising a light chain variable regionCDR1 comprising the amino acid sequence RASGNIHNYLA (SEQ ID NO:73), alight chain variable region CDR2 comprising the amino acid sequenceNAKTLAD (SEQ ID NO:74), and a light chain variable region CDR3comprising the amino acid sequence QHFWTSIT (SEQ ID NO:75). In someembodiments of the methods described herein, the anti-ILT2/ILT4 antibodycomprises: (a) a heavy chain variable region comprising a heavy chainvariable region CDR1 comprising the amino acid sequence GYTFTDYYMN (SEQID NO:70), a heavy chain variable region CDR2 comprising the amino acidsequence DFNPNNAGTTYNQKFEG (SEQ ID NO:118), and a heavy chain variableregion CDR3 comprising the amino acid sequence GRFYYGSLYSFDY (SEQ IDNO:72), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASGNIHNYLA (SEQID NO:73), a light chain variable region CDR2 comprising the amino acidsequence NAKTLAD (SEQ ID NO:74), and a light chain variable region CDR3comprising the amino acid sequence QHFWTSIT (SEQ ID NO:75). In someembodiments of the methods described herein, the anti-ILT2/ILT4 antibodycomprises: (a) a heavy chain variable region of SEQ ID NO:131 and (b) alight chain variable region of SEQ ID NO:132. In some embodiments of themethods described herein, the anti-ILT2/ILT4 antibody comprises: (a) aheavy chain variable region of SEQ ID NO:133 and (b) a light chainvariable region of SEQ ID NO:134. In some embodiments of the methodsdescribed herein, the anti-ILT2/ILT4 antibody comprises: (a) a heavychain of SEQ ID NO:148 and (b) a light chain of SEQ ID NO:149. In someembodiments of the methods described herein, the anti-ILT2/ILT4 antibodyis antibody 47H6. In some embodiments of the methods described herein,the anti-ILT2/ILT4 antibody is a humanized version of antibody 47H6. Insome embodiments of the methods described herein, the anti-ILT2/ILT4antibody is antibody Hz47H6.v2.

In some embodiments of the methods described herein, theILT2/ILT4-binding agent comprises a heavy chain variable region CDR1,CDR2, and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 ofantibody 51A1 or a humanized version of antibody 51A1.

In some embodiments of the method described herein, an ILT2/ILT4-bindingagent is an anti-ILT2/ILT4 antibody. In some embodiments of the methodsdescribed herein, the anti-ILT2/ILT4 antibody comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavychain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYGTMYYYAMDY (SEQ ID NO:88),and (b) a light chain variable region comprising a light chain variableregion CDR1 comprising the amino acid sequence RASESVDYYGNSFMY (SEQ IDNO:89), a light chain variable region CDR2 comprising the amino acidsequence FASNLES (SEQ ID NO:90), and a light chain variable region CDR3comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). In someembodiments of the methods described herein, the anti-ILT2/ILT4 antibodycomprises: (a) a heavy chain variable region of SEQ ID NO:135 and (b) alight chain variable region of SEQ ID NO:136. In some embodiments of themethods described herein, the anti-ILT2/ILT4 antibody is antibody 51A1.In some embodiments of the methods described herein, the anti-ILT2/ILT4antibody is a humanized version of antibody 51A1.

In some embodiments of the methods described herein, theILT2/ILT4-binding agent comprises a heavy chain variable region CDR1,CDR2, and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 ofantibody 64A12, a humanized version of antibody 64A12, or antibodyHz64A12.

In some embodiments of the method described herein, an ILT2/ILT4-bindingagent is an anti-ILT2/ILT4 antibody. In some embodiments of the methodsdescribed herein, the anti-ILT2/ILT4 antibody comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GFTFNTYAMH (SEQ ID NO:86), a heavychain variable region CDR2 comprising the amino acid sequenceRIRSKSSNYATYYADSVKD (SEQ ID NO:87), and a heavy chain variable regionCDR3 comprising the amino acid sequence DGIYYYDTMYYYAMDY (SEQ IDNO:102), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFIY(SEQ ID NO:103), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). Insome embodiments of the methods described herein, the anti-ILT2/ILT4antibody comprises: (a) a heavy chain variable region of SEQ ID NO:137and (b) a light chain variable region of SEQ ID NO:138. In someembodiments of the methods described herein, the anti-ILT2/ILT4 antibodycomprises: (a) a heavy chain variable region of SEQ ID NO:139 and (b) alight chain variable region of SEQ ID NO:140. In some embodiments of themethods described herein, the anti-ILT2/ILT4 antibody comprises: (a) aheavy chain of SEQ ID NO:152 and (b) a light chain of SEQ ID NO:153. Insome embodiments of the methods described herein, the anti-ILT2/ILT4antibody is antibody 64A12. In some embodiments of the methods describedherein, the anti-ILT2/ILT4 antibody is a humanized version of antibody64A12. In some embodiments of the methods described herein, theanti-ILT2/ILT4 antibody is antibody Hz64A12.

In some embodiments of the methods described herein, theILT2/ILT4-binding agent comprises a heavy chain variable region CDR1,CDR2, and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 ofantibody 73C4 or a humanized version of antibody 73C4.

In some embodiments of the method described herein, an ILT2/ILT4-bindingagent is an anti-ILT2/ILT4 antibody. In some embodiments of the methodsdescribed herein, the anti-ILT2/ILT4 antibody comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYMN (SEQ ID NO:70), a heavychain variable region CDR2 comprising the amino acid sequenceNVNPNNGGTSYNQKFKG (SEQ ID NO:106), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). Insome embodiments of the methods described herein, the anti-ILT2/ILT4antibody comprises: (a) a heavy chain variable region of SEQ ID NO:141and (b) a light chain variable region of SEQ ID NO:142. In someembodiments of the methods described herein, the anti-ILT2/ILT4 antibodyis antibody 73C4. In some embodiments of the methods described herein,the anti-ILT2/ILT4 antibody is a humanized version of antibody 73C4.

In some embodiments of the methods described herein, theILT2/ILT4-binding agent comprises a heavy chain variable region CDR1,CDR2, and CDR3 and a light chain variable region CDR1, CDR2, and CDR3 ofantibody 73D1, a humanized version of antibody 73D1, or antibodyHz73D1.v1.

In some embodiments of the method described herein, an ILT2/ILT4-bindingagent is an anti-ILT2/ILT4 antibody. In some embodiments of the methodsdescribed herein, the anti-ILT2/ILT4 antibody comprises: (a) a heavychain variable region comprising a heavy chain variable region CDR1comprising the amino acid sequence GYTFTDYYIN (SEQ ID NO:111), a heavychain variable region CDR2 comprising the amino acid sequenceNVNPNDGGTTYNQKFKG (SEQ ID NO:112), and a heavy chain variable regionCDR3 comprising the amino acid sequence REIYFYGTIYYYAMDY (SEQ IDNO:107), and (b) a light chain variable region comprising a light chainvariable region CDR1 comprising the amino acid sequence RASESVDYYGNSFMY(SEQ ID NO:89), a light chain variable region CDR2 comprising the aminoacid sequence FASNLES (SEQ ID NO:90), and a light chain variable regionCDR3 comprising the amino acid sequence QQNNEDPWT (SEQ ID NO:91). Insome embodiments of the methods described herein, the anti-ILT2/ILT4antibody comprises: (a) a heavy chain variable region of SEQ ID NO:143and (b) a light chain variable region of SEQ ID NO:142. In someembodiments of the methods described herein, the anti-ILT2/ILT4 antibodycomprises: (a) a heavy chain variable region of SEQ ID NO:144 and (b) alight chain variable region of SEQ ID NO:145. In some embodiments of themethods described herein, the anti-ILT2/ILT4 antibody comprises: (a) aheavy chain of SEQ ID NO:156 and (b) a light chain of SEQ ID NO:157. Insome embodiments of the methods described herein, the anti-ILT2/ILT4antibody is antibody 73D1. In some embodiments of the methods describedherein, the anti-ILT2/ILT4 antibody is a humanized version of antibody73D1. In some embodiments of the methods described herein, theanti-ILT2/ILT4 antibody is antibody Hz73D1.v1.

In some embodiments of the methods described herein, a method comprisesadministering an ILT-binding agent (e.g., an ILT2-binding agent, anILT4-binding agent, or an ILT2/ILT4-binding agent) described herein incombination with at least one additional therapeutic agent ortherapeutic therapy. In some embodiments of the methods describedherein, a method comprises administering an ILT2/ILT4-binding agentdescribed herein in combination with at least one additional therapeuticagent or therapeutic therapy. Treatment with two or more therapeuticagents often uses agents that work by different mechanisms of action,although this is not required. Combination therapy using agents withdifferent mechanisms of action may result in additive or synergeticeffects. Combination therapy may allow for a lower dose of each agentthan is used in monotherapy, thereby reducing toxic side effects and/orincreasing the therapeutic index of the agent(s). Combination therapymay decrease the likelihood that resistance to an agent will develop.

In some embodiments of the methods described, the combination of anILT-binding agent (e.g., an ILT2-binding agent, an ILT4-binding agent,or an ILT2/ILT4-binding agent) described herein and at least oneadditional therapeutic agent results in additive or synergistic results.In some embodiments, the combination therapy results in an increase inthe therapeutic index of the ILT-binding agent. In some embodiments, thecombination therapy results in an increase in the therapeutic index ofthe additional therapeutic agent(s). In some embodiments, thecombination therapy results in a decrease in the toxicity and/or sideeffects of the ILT-binding agent. In some embodiments, the combinationtherapy results in a decrease in the toxicity and/or side effects of theadditional therapeutic agent(s). In some embodiments, combinationtherapy comprises a therapeutic agent that affects the immune response(e.g., enhances or activates the response) and a therapeutic agent thataffects (e.g., inhibits or kills) the tumor/cancer cells.

In some embodiments of the methods described herein, a combinationtreatment comprises one additional therapeutic agent. In someembodiments of the methods described herein, a combination treatmentcomprises at least one additional therapeutic agent. In some embodimentsof the methods described herein, a combination treatment comprises twoor more additional therapeutic agents.

Useful classes of therapeutic agents include, but are not limited to,anti-tubulin agents, auristatins, DNA minor groove binders, DNAreplication inhibitors, alkylating agents (e.g., platinum complexes suchas cisplatin, mono(platinum), bis(platinum) and tri-nuclear platinumcomplexes and carboplatin), anthracyclines, antibiotics, anti-folates,anti-metabolites, chemotherapy sensitizers, duocarmycins, etoposides,fhiorinated pyrimidines, ionophores, lexitropsins, nitrosoureas,platinols, purine antimetabolites, puromycins, radiation sensitizers,steroids, taxanes, topoisomerase inhibitors, vinca alkaloids, or thelike. In some embodiments, the second therapeutic agent is an alkylatingagent, an antimetabolite, an antimitotic, a topoisomerase inhibitor, oran angiogenesis inhibitor.

Therapeutic agents that may be administered in combination with theILT-binding agents described herein include chemotherapeutic agents.Thus, in some embodiments, the method or treatment involves theadministration of an ILT-binding agent of the present disclosure incombination with a chemotherapeutic agent or in combination with acocktail of chemotherapeutic agents.

Chemotherapeutic agents useful in the present disclosure include, butare not limited to, alkylating agents such as thiotepa andcyclophosphamide (CYTOXAN); alkyl sulfonates such as busulfan,improsulfan and piposulfan; aziridines such as benzodopa, carboquone,meturedopa, and uredopa; ethylenimines and methylamelamines includingaltretamine, triethylenemelamine, trietylenephosphoramide,triethylenethiophosphaoramide and trimethylolomelamime; nitrogenmustards such as chlorambucil, chlornaphazine, cholophosphamide,estramustine, ifosfamide, mechlorethamine, mechlorethamine oxidehydrochloride, melphalan, novembichin, phenesterine, prednimustine,trofosfamide, uracil mustard; nitrosureas such as carmustine,chlorozotocin, fotemustine, lomustine, nimustine, ranimustine;antibiotics such as aclacinomysins, actinomycin, authramycin, azaserine,bleomycins, cactinomycin, calicheamicin, carabicin, caminomycin,carzinophilin, chromomycins, dactinomycin, daunorubicin, detorubicin,6-diazo-5-oxo-L-norleucine, doxorubicin, epirubicin, esorubicin,idarubicin, marcellomycin, mitomycins, mycophenolic acid, nogalamycin,olivomycins, peplomycin, potfiromycin, puromycin, quelamycin,rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex,zinostatin, zorubicin; anti-metabolites such as methotrexate and5-fluorouracil (5-FU); folic acid analogues such as denopterin,methotrexate, pteropterin, trimetrexate; purine analogs such asfludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidineanalogs such as ancitabine, azacitidine, 6-azauridine, carmofur,cytosine arabinoside, dideoxyuridine, doxifluridine, enocitabine,floxuridine, 5-FU; androgens such as calusterone, dromostanolonepropionate, epitiostanol, mepitiostane, testolactone; anti-adrenals suchas aminoglutethimide, mitotane, trilostane; folic acid replenishers suchas folinic acid; aceglatone; aldophosphamide glycoside; aminolevulinicacid; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine;demecolcine; diaziquone; elformithine; elliptinium acetate; etoglucid;gallium nitrate; hydroxyurea; lentinan; lonidamine; mitoguazone;mitoxantrone; mopidamol; nitracrine; pentostatin; phenamet; pirarubicin;podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK; razoxane;sizofuran; spirogermanium; tenuazonic acid; triaziquone;2,2′,2″-trichlorotriethylamine; urethan; vindesine; dacarbazine;mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine;arabinoside (Ara-C); taxoids, e.g. paclitaxel (TAXOL) and docetaxel(TAXOTERE); chlorambucil; gemcitabine; 6-thioguanine; mercaptopurine;platinum analogs such as cisplatin and carboplatin; vinblastine;platinum; etoposide (VP-16); ifosfamide; mitomycin C; mitoxantrone;vincristine; vinorelbine; navelbine; novantrone; teniposide; daunomycin;aminopterin; ibandronate; CPT 11; topoisomerase inhibitor RFS 2000;difluoromethylornithine (DMFO); retinoic acid; esperamicins;capecitabine (XELODA); and pharmaceutically acceptable salts, acids orderivatives of any of the above.

Chemotherapeutic agents also include anti-hormonal agents that act toregulate or inhibit hormone action on tumors such as anti-estrogensincluding for example tamoxifen, raloxifene, aromatase inhibiting4(5)-imidazoles, 4-hydroxytamoxifen, trioxifene, keoxifene, LY117018,onapristone, and toremifene (FARESTON); and anti-androgens such asflutamide, nilutamide, bicalutamide, leuprolide, and goserelin; andpharmaceutically acceptable salts, acids or derivatives of any of theabove.

In some embodiments of the methods described herein, thechemotherapeutic agent is a topoisomerase inhibitor. Topoisomeraseinhibitors are chemotherapy agents that interfere with the action of atopoisomerase enzyme (e.g., topoisomerase I or II). Topoisomeraseinhibitors include, but are not limited to, doxorubicin HC1,daunorubicin citrate, mitoxantrone HC1, actinomycin D, etoposide,topotecan HC1, teniposide (VM-26), and irinotecan, as well aspharmaceutically acceptable salts, acids, or derivatives of any ofthese. In some embodiments, the additional therapeutic agent isirinotecan.

In some embodiments, the chemotherapeutic agent is an anti-metabolite.An anti-metabolite is a chemical with a structure that is similar to ametabolite required for normal biochemical reactions, yet differentenough to interfere with one or more normal functions of cells, such ascell division. Anti-metabolites include, but are not limited to,gemcitabine, fluorouracil, capecitabine, methotrexate sodium,ralitrexed, pemetrexed, tegafur, cytosine arabinoside, thioguanine,5-azacytidine, 6-mercaptopurine, azathioprine, 6-thioguanine,pentostatin, fludarabine phosphate, and cladribine, as well aspharmaceutically acceptable salts, acids, or derivatives of any ofthese. In some embodiments, the additional therapeutic agent isgemcitabine.

In some embodiments of the methods described herein, thechemotherapeutic agent is an antimitotic agent, including, but notlimited to, agents that bind tubulin. In some embodiments, the agent isa taxane. In some embodiments, the agent is paclitaxel or docetaxel, ora pharmaceutically acceptable salt, acid, or derivative of paclitaxel ordocetaxel. In some embodiments, the agent is paclitaxel (TAXOL),docetaxel (TAXOTERE), albumin-bound paclitaxel (nab-paclitaxel;ABRAXANE), DHA-paclitaxel, or PG-paclitaxel. In certain alternativeembodiments, the antimitotic agent comprises a vinca alkaloid, such asvincristine, vinblastine, vinorelbine, or vindesine, or pharmaceuticallyacceptable salts, acids, or derivatives thereof. In some embodiments,the antimitotic agent is an inhibitor of kinesin Eg5 or an inhibitor ofa mitotic kinase such as Aurora A or Plkl. In some embodiments, theadditional therapeutic agent is paclitaxel. In some embodiments, theadditional therapeutic agent is nab-paclitaxel.

In some embodiments of the methods described herein, an additionaltherapeutic agent comprises an agent such as a small molecule. Forexample, treatment can involve the combined administration of anILT-binding agent of the present disclosure with a small molecule thatacts as an inhibitor against tumor-associated antigens including, butnot limited to, EGFR, HER2 (ErbB2), and/or VEGF. In some embodiments, anILT-binding agent (e.g., an anti-ILT2 antibody, an anti-ILT4 antibody,or an anti-ILT2/ILT4 antibody) of the present disclosure is administeredin combination with a protein kinase inhibitor selected from the groupconsisting of: gefitinib (IRESSA), erlotinib (TARCEVA), sunitinib(SUTENT), lapatanib, vandetanib (ZACTIMA), AEE788, CI-1033, cediranib(RECENTIN), sorafenib (NEXAVAR), and pazopanib (GW786034B). In someembodiments, an additional therapeutic agent comprises an mTORinhibitor.

In some embodiments of the methods described herein, an additionaltherapeutic agent comprises a biological molecule, such as an antibody.For example, treatment can involve the combined administration of anILT-binding agent of the present disclosure with antibodies againsttumor-associated antigens including, but not limited to, antibodies thatbind EGFR, HER2/ErbB2, and/or VEGF.

In some embodiments, the additional therapeutic agent is an antibodythat is an angiogenesis inhibitor (e.g., an anti-VEGF or VEGF receptorantibody). In some embodiments, the additional therapeutic agent isbevacizumab (AVASTIN), ramucirumab, trastuzumab (HERCEPTIN), pertuzumab(OMNITARG), panitumumab (VECTIBIX), nimotuzumab, zalutumumab, orcetuximab (ERBITUX).

In some embodiments of the methods described herein, the additionaltherapeutic agent is an immunotherapeutic agent. In some embodiments ofthe methods described herein the immunotherapeutic agent is selectedfrom the group consisting of: a modulator of PD-1 activity, a modulatorof PD-L1 activity, a modulator of PD-L2 activity, a modulator of CTLA-4activity, a modulator of CD28 activity, a modulator of CD80 activity, amodulator of CD86 activity, a modulator of 4-1BB activity, an modulatorof OX40 activity, a modulator of KIR activity, a modulator of Tim-3activity, a modulator of LAG3 activity, a modulator of CD27 activity, amodulator of CD40 activity, a modulator of GITR activity, a modulator ofTIGIT activity, a modulator of CD20 activity, a modulator of CD96activity, a modulator of IDO1 activity,

In some embodiments of the methods described herein, animmunotherapeutic agent is selected from the group consisting of: a PD-1antagonist, a PD-L1 antagonist, a PD-L2 antagonist, a CTLA-4 antagonist,a CD80 antagonist, a CD86 antagonist, a KIR antagonist, a Tim-3antagonist, a LAG3 antagonist, a TIGIT antagonist, a CD20 antagonist, aCD96 antagonist, and/or an IDO1 antagonist.

In some embodiments of the methods described herein, the additionaltherapeutic agent is a checkpoint inhibitor. In some embodiments, theadditional therapeutic agent is an anti-PD-1 antibody, an anti-PD-L1antibody, an anti-PD-L2 antibody, an anti-CTLA-4 antibody, or ananti-TIGIT antibody, an anti-CD28 antibody, an anti-CD80 antibody, ananti-CD86 antibody, an anti-4-1BB antibody, an anti-OX40 antibody, ananti-KIR antibody, an anti-Tim-3 antibody, an anti-LAG3 antibody, ananti-CD27 antibody, an anti-CD40 antibody, an anti-GITR antibody, ananti-TIGIT antibody, an anti-CD20 antibody, an anti-CD96 antibody, or ananti-IDO1 antibody. In some embodiments, the additional therapeuticagent is an anti-HLA-G antibody. In some embodiments, the additionaltherapeutic agent is B7-1 (CD80), B7-2 (CD86), 4-1BB ligand, or ananti-CD3 antibody.

In some embodiments of the methods described herein, the PD-1 antagonistis an antibody that specifically binds PD-1. In some embodiments, theantibody that binds PD-1 is Pembrolizumab (MK-3475; KEYTRUDA),Pidilizumab (CT-011), Nivolumab (OPDIVO), Durvalumab (MEDI0680),Cemiplimab (REGN2810), Tislelizumab (BGB-A317), Spartalizumab (PDR-001),or STI-A1110. Exemplary anti-PD-1 antibodies are provided, for example,in U.S. Pat. Nos. 10,316,089, 9,580,504, 9,856,320, 8,609,089, and8,952,136; the contents of all of which are incorporated by reference intheir entirety herein. In some embodiments, the antibody that binds PD-1is described in PCT Publication WO 2014/179664, for example, an antibodyidentified as APE2058, APE1922, APE1923, APE1924, APE 1950, or APE1963,or an antibody containing the CDR regions of any of these antibodies. Inother embodiments, the PD-1 antagonist is a fusion protein that includesPD-L2, for example, AMP-224. In other embodiments, the PD-1 antagonistis a peptide inhibitor, for example, AU P-12.

In some embodiments, the PD-L1 antagonist is an antibody thatspecifically binds PD-L1. In some embodiments, the antibody that bindsPD-L1 is Atezolizumab (TECENTRIQ), MEDI4736, BMS-936559 (MDX-1105),Avelumab (BAVENCIO), Durvalumab (IMFINZI), KD033, the antibody portionof KD033, or STI-A1014. In some embodiments, the antibody that bindsPD-L1 is described in PCT Publication WO 2014/055897, for example,Ab-14, Ab-16, Ab-30, Ab-31, Ab-42, Ab-50, Ab-52, or Ab-55, or anantibody that contains the CDR regions of any of these antibodies.

In some embodiments, the CTLA-4 antagonist is an antibody thatspecifically binds CTLA-4. In some embodiments, the antibody that bindsCTLA-4 is Ipilimumab (YERVOY) or Tremelimumab (CP-675,206). In someembodiments, the CTLA-4 antagonist a CTLA-4 fusion protein, for example,KAHR-102.

In some embodiments, the LAG3 antagonist is an antibody thatspecifically binds LAG3. In some embodiments, the antibody that bindsLAG3 is IMP701, IMP731, BMS-986016, LAG525, and GSK2831781. In someembodiments, the LAG3 antagonist includes a soluble LAG3 receptor, forexample, IMP321.

In some embodiments, the KIR antagonist is an antibody that specificallybinds KIR. In some embodiments, the antibody that binds KIR isLirilumab.

In some embodiments, an immunotherapeutic agent is selected from thegroup consisting of: a CD28 agonist, a 4-1BB agonist, an OX40 agonist, aCD27 agonist, a CD80 agonist, a CD86 agonist, a CD40 agonist, and a GITRagonist.

In some embodiments, the OX40 agonist includes OX40 ligand, or anOX40-binding portion thereof. For example, the OX40 agonist may beMEDI6383. In some embodiments, the OX40 agonist is an antibody thatspecifically binds OX40. In some embodiments, the antibody that bindsOX40 is MEDI6469, MEDI0562, PF-8600, or MOXR0916 (RG7888). In someembodiments, the OX40 agonist is a vector (e.g., an expression vector orvirus, such as an adenovirus) capable of expressing OX40 ligand. In someembodiments the OX40-expressing vector is Delta -24-RGDOX or DNX2401.

In some embodiments, the 4-1BB (CD137) agonist is a binding molecule,such as an anticalin. In some embodiments, the anticalin is PRS-343. Insome embodiments, the 4-1BB agonist is an antibody that specificallybinds 4-1BB. In some embodiments, antibody that binds 4-1BB isUtomilumab (PF-05082566) or Urelumab (BMS-663513).

In some embodiments, the CD27 agonist is an antibody that specificallybinds CD27. In some embodiments, the antibody that binds CD27 isvarlilumab (CDX-1127).

In some embodiments, the GITR agonist comprises a GITR ligand or aGITR-binding portion thereof. In some embodiments, the GITR agonist isan antibody that specifically binds GITR. In some embodiments, theantibody that binds GITR is TRX518, MK-4166, or INBRX-110.

In some embodiments of the methods described herein, the additionaltherapeutic agent is a biologic molecule, such as, a cytokine, achemokine, a growth factor, an interferon, an interleukin, a lymphokine,a member of the tumor necrosis factor (TNF) family, and animmunostimulatory oligonucleotide (e.g., CpG dinucleotides). In someembodiments, the biologic molecule is selected from the group consistingof: adrenomedullin (AM), angiopoietin (Ang), BMPs, BDNF, EGF,erythropoietin (EPO), FGF, GDNF, granulocyte-macrophage colonystimulating factor (GM-CSF), macrophage colony stimulating factor(M-CSF), granulocyte colony stimulating factor (G-CSF), GDF9, HGF, HDGF,IGF, migration-stimulating factor, myostatin (GDF-8), NGF,neurotrophins, PDGF, thrombopoietin, TGF-a, TGF-β, TNF-α, VEGF, PIGF,IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-12, IL-15, and IL-18.

Furthermore, treatment with an ILT-binding agent (e.g., an ILT2-bindingagent, an ILT4-binding agent, or an ILT2/ILT4-binding agent) describedherein can be accompanied by surgical removal of tumors, removal ofcancer cells, or any other therapy deemed necessary by a treatingphysician.

In some embodiments, treatment with an ILT-binding agent (e.g., anILT2-binding agent, an ILT4-binding agent, or an ILT2/ILT4-bindingagent) can occur prior to, concurrently with, or subsequent toadministration of the additional therapeutic agents. In someembodiments, combined administration includes co-administration, eitherin a single pharmaceutical formulation or using separate formulations,or consecutive administration in either order but generally within atime period such that all active agents can exert their biologicalactivities. In some embodiments, preparation of agents and/or dosingschedules for additional therapeutic agents are according tomanufacturers' instructions or as determined empirically by the skilledpractitioner.

In some embodiments of the methods described herein, an ILT-bindingagent (e.g., an ILT2-binding agent, an ILT4-binding agent, or anILT2/ILT4-binding agent) is administered to a subject as part of acombination therapy.

It will be appreciated that the combination of an ILT-binding agent(e.g., an ILT2-binding agent, an ILT4-binding agent, or anILT2/ILT4-binding agent) described herein and at least one additionaltherapeutic agent may be administered in any order or concurrently. Insome embodiments, an ILT-binding agent is administered to subjects thathave previously undergone treatment with a therapeutic agent. In someembodiments, an ILT-binding agent and a second therapeutic agent areadministered substantially simultaneously or concurrently. For example,a subject may be given an ILT-binding agent while undergoing a course oftreatment with a second therapeutic agent (e.g., a chemotherapeuticagent). In some embodiments, an ILT-binding agent is administered within1 year of the treatment with a second therapeutic agent. In someembodiments, an ILT-binding agent is administered within 10, 8, 6, 4, or2 months of any treatment with a second therapeutic agent. In someembodiments, an ILT-binding agent is administered within 4, 3, 2, or 1weeks of any treatment with a second therapeutic agent. In someembodiments, an ILT-binding agent is administered within 5, 4, 3, 2, or1 days of any treatment with a second therapeutic agent. It will furtherbe appreciated that the two (or more) agents or treatments can beadministered to the subject within a matter of hours or minutes (i.e.,substantially simultaneously).

For the treatment of a disease, the appropriate dosage of an ILT-bindingagent (e.g., an ILT2-binding agent, an ILT4-binding agent, or anILT2/ILT4-binding agent) of the present disclosure depends on thedisorder or disease to be treated, the severity and course of thedisorder or disease, the responsiveness of the disorder or disease,whether the agent is administered for therapeutic or preventativepurposes, previous therapy, the patient's clinical history, and so on.An ILT-binding agent can be administered one time or over a series oftreatments lasting from several days to several months, or until a cureis effected or a diminution of the disease state is achieved.

The present disclosure provides pharmaceutical compositions comprisingan ILT-binding agent described herein and a pharmaceutically acceptablevehicle. The present disclosure also provides pharmaceuticalcompositions comprising an ILT2-binding agent described herein and apharmaceutically acceptable vehicle. The present disclosure alsoprovides pharmaceutical compositions comprising an ILT4-binding agentdescribed herein and a pharmaceutically acceptable vehicle. The presentdisclosure also provides pharmaceutical compositions comprising anILT2/ILT4-binding agent described herein and a pharmaceuticallyacceptable vehicle.

Formulations are prepared for storage and use by combining a purifiedantibody or agent of the present disclosure with a pharmaceuticallyacceptable vehicle (e.g., a carrier or excipient). Those of skill in theart generally consider pharmaceutically acceptable carriers, excipients,and/or stabilizers to be inactive ingredients of a formulation orpharmaceutical composition.

Suitable pharmaceutically acceptable vehicles include, but are notlimited to, nontoxic buffers such as phosphate, citrate, and otherorganic acids; salts such as sodium chloride; antioxidants includingascorbic acid and methionine; preservatives such asoctadecyldimethylbenzyl ammonium chloride, hexamethonium chloride,benzalkonium chloride, benzethonium chloride, phenol, butyl or benzylalcohol, alkyl parabens, such as methyl or propyl paraben, catechol,resorcinol, cyclohexanol, 3-pentanol, and m-cresol; low molecular weightpolypeptides (e.g., less than about 10 amino acid residues); proteinssuch as serum albumin, gelatin, or immunoglobulins; hydrophilic polymerssuch as polyvinylpyrrolidone; amino acids such as glycine, glutamine,asparagine, histidine, arginine, or lysine; carbohydrates such asmonosaccharides, disaccharides, glucose, mannose, or dextrins; chelatingagents such as EDTA; sugars such as sucrose, mannitol, trehalose orsorbitol; salt-forming counter-ions such as sodium; metal complexes suchas Zn-protein complexes; and non-ionic surfactants such as TWEEN orpolyethylene glycol. (Remington: The Science and Practice of Pharmacy,22^(nd) Edition, 2012, Pharmaceutical Press, London.). In someembodiments, the formulation is in the form of an aqueous solution. Insome embodiments, the formulation is stored in a lyophilized or in analternative dried form.

The ILT-binding agents of the present disclosure can be formulated inany suitable form for delivery to a target cell/tissue. In someembodiments, an ILT-binding agent (e.g., an ILT2-binding agent, anILT4-binding agent, or an ILT2/ILT4-binding agent) can be formulated asa liposome, microparticle, microcapsule, albumin microsphere,microemulsion, nanoparticle, nanocapsule, or macroemulsion.

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4-binding agent) is formulated withliposomes. Methods to produce liposomes are known to those of skill inthe art. For example, some liposomes can be generated by reverse phaseevaporation with a lipid composition comprising phosphatidylcholine,cholesterol, and PEG-derivatized phosphatidylethanolamine (PEG-PE).

In some embodiments, an ILT-binding agent (e.g., an ILT2-binding agent,an ILT4-binding agent, or an ILT2/ILT4-binding agent) is formulated as asustained-release preparation. Suitable examples of sustained-releasepreparations include semi-permeable matrices of solid hydrophobicpolymers containing an agent, where the matrices are in the form ofshaped articles (e.g., films or microcapsules). Sustained-releasematrices include but are not limited to polyesters, hydrogels such aspoly(2-hydroxyethyl-methacrylate) or poly(vinyl alcohol), polylactides,copolymers of L-glutamic acid and 7 ethyl-L-glutamate, non-degradableethylene-vinyl acetate, degradable lactic acid-glycolic acid copolymerssuch as the LUPRON DEPOT™ (injectable microspheres composed of lacticacid-glycolic acid copolymer and leuprolide acetate), sucrose acetateisobutyrate, and poly-D-(−)-3-hydroxybutyric acid.

The pharmaceutical compositions or formulations of the presentdisclosure can be administered in any number of ways for either local orsystemic treatment. Administration can be topical by epidermal ortransdermal patches, ointments, lotions, creams, gels, drops,suppositories, sprays, liquids and powders; pulmonary by inhalation orinsufflation of powders or aerosols, including by nebulizer,intratracheal, and intranasal; oral; or parenteral includingintravenous, intraarterial, intratumoral, subcutaneous, intraperitoneal,intramuscular (e.g., injection or infusion), or intracranial (e.g.,intrathecal or intraventricular).

EXAMPLES Example 1 Generation of Antibodies and Screening of Antibodies

Anti-ILT antibodies were generated using the extracellular domain ofhuman ILT2, the extracellular domain of human ILT4, and/or theextracellular domain of rhesus ILT2 as the immunogen. For examples,anti-ILT2 antibodies were generated using the extracellular domain ofhuman ILT2. Similarly, anti-ILT4 antibodies were generated using theextracellular domain of human ILT4. Anti-ILT2/ILT4 antibodies weregenerated using a mixture of the extracellular domain of human ILT2, theextracellular domain of human ILT4, and the extracellular domain ofrhesus ILT2. Single cell suspensions of lymphocytes were obtained fromthe spleens and lymph nodes of immunized mice after the individualanimals had been determined to have suitable antibody titers.Lymphocytes were fused with murine myeloma cells by standard methods.Hybridoma fusions were plated onto semi-solid media for HAT selection.After 5-7 days, single colonies were selected using a ClonePix™ systemand plated into 96-well plates.

ELISA assays were used to screen antibodies against human ILT2, humanILT4, and rhesus ILT2. Antibodies that bound to human ILT2 only, humanILT4 only, or human ILT2, human ILT4 and rhesus ILT2 were selected.

Example 2 Synteny Between Human and Cynomolgus Monkey ILT2 and ILT4Genes

In rodents, paired Ig-like receptor B (PirB) and gp49B1 have beendescribed as the potential orthologues of human LILRB family ofreceptors (Kang X, et al. Cell Cycle. (2016);15(1):25-40). However, PirBand gp49B1 show less than 50% identity to both human ILT2 and humanILT4. Further, marked differences exist in the receptor/ligand pairingamong the rodent and human LILRB family members and the biologicalfunction of the rodent receptors are unclear. Thus, rodents are notconsidered relevant species to test the biological effects of anti-ILTantibodies.

An analysis of genomic structure (synteny) was used to identifycandidate orthologs of both human ILT2 and ILT4 in cynomolgus monkey.The genomic organization of the locus that contains the LILR familymembers in human (hg38) and cynomolgus monkey (Macaca fascicularisv5.0.95, “cyno”) were compared using the gene annotations provided byEnsembl. In cases where annotations were not found, manual analysis ofthe intervening sequence was used to confirm lack of an open readingframe. The predicted protein sequence of genes in cynomolgus monkeywithout pre-annotated gene symbols was compared to all human genes usingblastp tools on UniProt to find the most likely human ortholog based onthe identity score.

It was found that the cynomolgus monkey genomic organization is missinga gene at the same genome location as human LILRB2 (ILT4), whileretaining a gene at the same location as human LILRB1 (ILT2). A similarorganization was observed with rhesus macaque. The sequence identitybetween human ILT2, human ILT4 and cyno ILT2 ranges from 73%-80%. Thesequence identity between human ILT2 and cyno ILT2 is 73%, whilesequence identity between human ILT4 and cyno ILT2 is 78%. Incomparison, the sequence identity between human ILT2 and human ILT4 is80%.

Example 3 Binding Characteristics of Anti-Human ILT2, ILT4, andILT2/ILT4 Antibodies

The binding affinities of anti-ILT2 and anti-ILT4 antibodies weremeasured using a Biacore system (GE Healthcare LifeSciences).Equilibrium dissociation constant (K_(D)) measurements were carried outwith purified antibodies to evaluate their binding to human ILT2, humanILT4, and rhesus ILT2. Briefly, purified anti-ILT2 antibody 27F9,anti-ILT4 antibodies 47C8 and 48A5, and anti-ILT2/ILT4 antibodies 47H6,51A1, 64A12, 73C4, and 73D1 were captured on a Sensor Chip Protein A (GEHealthCare). The surface of the Biacore Sensor Chip Protein A consistsof a carboxymethylated dextran matrix with a recombinant Protein Avariant covalently attached. Soluble human ILT2-ECD, human ILT4-ECD, orrhesus ILT2-ECD were injected at a flow rate of 30 μL/min at 25° C. TheILT2 or ILT4 proteins were used at concentrations ranging from 1.6-200nM in PBS-P buffer with 2 fold dilutions. Kinetic data were collectedover time and fit using the simultaneous global fit equation to yieldaffinity constants (K_(D) values) for each antibody.

Binding data is shown in Tables 9A and 9B.

TABLE 9A Human ILT2 Human ILT4 K_(on) K_(off) K_(D) K_(on) K_(off) K_(D)Antibody [1/Ms] [s⁻¹] M [1/Ms] [s⁻¹] M 27F9 2.1 × 10⁵ 5.4 × 10⁻⁵  2.6 ×10⁻¹⁰ NB NB NB 47C8 NB NB NB 3.4 × 10⁵ 2.5 × 10⁻⁵ 7.4 × 10⁻¹¹ 48A5 NB NBNB 8.1 × 10⁵ 2.1 × 10⁻⁵ 2.6 × 10⁻¹¹ 47H6 4.2 × 10⁴ 8.6 × 10⁻⁵ 2.1 × 10⁻⁹3.7 × 10⁴ 2.8 × 10⁻⁵ 7.6 × 10⁻¹⁰ 51A1 3.9 × 10⁴ 2.2 × 10⁻⁴ 5.8 × 10⁻⁹6.8 × 10⁴ 1.4 × 10⁻⁵ 2.0 × 10⁻¹⁰ 64A12¹ 2.0 × 10⁴ ~1.0 × 10⁻⁵  <1.0 ×10⁻¹⁰  8.2 × 10⁴ ~1.0 × 10⁻⁵  <1.0 × 10⁻¹⁰  73C4¹ 3.1 × 10⁴ ~1.0 × 10⁻⁵ <1.0 × 10⁻¹⁰  9.7 × 10⁴ ~1.0 × 10⁻⁵  <1.0 × 10⁻¹⁰  73D1 5.0 × 10⁴ 6.0 ×10⁻⁵ 1.2 × 10⁻⁹ 3.0 × 10⁵ 5.4 × 10⁻⁵ 1.8 × 10⁻¹⁰ ¹Binding assay wasperformed under low resolution parameters

TABLE 9B Rhesus ILT2 K_(on) K_(off) K_(D) Antibody [1/Ms] [s⁻¹] M 27F9NB NB NB 47C8 5.9 × 10⁵ 1.4 × 10⁻³ 2.3 × 10⁻⁹ 48A5 1.1 × 10⁶ 2.6 × 10⁻³2.3 × 10⁻⁹ 47H6¹ 4.7 × 10⁴  ~1 × 10⁻⁵ <1.0 × 10⁻¹⁰  51A1 1.0 × 10⁵ 2.1 ×10⁻⁵  2.0 × 10⁻¹⁰ 64A12¹ 2.0 × 10⁴ ~1.0 × 10⁻⁵  <1.0 × 10⁻¹⁰  73C4¹ 3.1× 10⁴ ~1.0 × 10⁻⁵  <1.0 × 10⁻¹⁰  73D1 5.0 × 10⁴ 6.0 × 10⁻⁵ 1.2 × 10⁻⁹¹Binding assay was performed under low resolution parameters

Example 4 Sequence Analyses of Anti-ILT2, Anti-ILT4, and Anti-ILT2/ILT4Antibodies

Representative anti-ILT2 antibody 27F9, anti-ILT4 antibodies 47C8 and48A5, and anti-ILT2/ILT4 antibodies 47H6, 51A1, 64A12, 73C4, and 73D1were sequenced and the heavy chain variable region and light chainvariable region amino acid sequences are disclosed herein and summarizedin Table 10.

TABLE 10 Heavy Chain Variable Light Chain Variable Antibody TargetRegion Region 27F9 ILT2 SEQ ID NO: 125 SEQ ID NO: 126 47C8 ILT4 SEQ IDNO: 127 SEQ ID NO: 128 48A5 ILT4 SEQ ID NO: 129 SEQ ID NO: 130 47H6ILT2/ILT4 SEQ ID NO: 131 SEQ ID NO: 132 51A1 ILT2/ILT4 SEQ ID NO: 135SEQ ID NO: 136 64A12 ILT2/ILT4 SEQ ID NO: 137 SEQ ID NO: 138 73C4ILT2/ILT4 SEQ ID NO: 141 SEQ ID NO: 142 73D1 ILT2/ILT4 SEQ ID NO: 143SEQ ID NO: 142

The heavy chain and light chain variable region CDRs for the individualantibodies are disclosed in Tables 1-8 and as SEQ ID NOs:22-124.

Example 5 Generation of Humanized Antibodies

Several of the anti-ILT2/ILT4 antibodies, i.e., 47H6, 64A12, and 73D1,were humanized by methods known to those skilled in the art. Thesehumanized antibodies are referred to herein as Hz47H6.v2, Hz64A12, andHz73D1.v1, respectively. During the humanization process for antibody47H6, the heavy chain variable region CDR2 was modified fromDFNPNNGGTTYNQKFEG (SEQ ID NO:71) to DFNPNNAGTTYNQKFEG (SEQ ID NO:118).The heavy chain variable region sequence of Hz47H6.v2 is SEQ ID NO:133and the light chain variable region sequence of Hz47H6.v2 is SEQ IDNO:134; the heavy chain variable region sequence of Hz64A12 is SEQ IDNO:139 and the light chain variable region sequence of Hz64A12 is SEQ IDNO:140; and the heavy chain variable region sequence of Hz73D1.v1 is SEQID NO:144 and the light chain variable region sequence of Hz73D1.v1 isSEQ ID NO:145.

The binding affinities of the humanized antibodies to human ILT2 andhuman ILT4 were measured using a Biacore system as described herein. Thebinding affinities of antibodies Hz47H6.v2, Hz64A12, and Hz73D1.v1 areshown in Table 11 as compared with the parental antibodies.

TABLE 11 Human ILT2 Human ILT4 K_(on) K_(off) K_(D) K_(on) K_(off) K_(D)Antibody [1/Ms] [s⁻¹] M [1/Ms] [s⁻¹] M 47H6 1.0 × 10⁵ 2.1 × 10⁻⁵  2.0 ×10⁻¹⁰ 1.0 × 10⁵ 2.1 × 10⁻⁵ 2.0 × 10⁻¹⁰ Hz47H6.v2 2.3 × 10⁵ 9.0 × 10⁻⁴4.0 × 10⁻⁹ 8.7 × 10⁴ 1.8 × 10⁻⁴ 2.0 × 10⁻⁹  64A12¹ 2.0 × 10⁴ ~1.0 ×10⁻⁵  <1.0 × 10⁻¹⁰  8.2 × 10⁴ ~1.0 × 10⁻⁵  <1.0 × 10⁻¹⁰  Hz64A12¹ 9.3 ×10⁴ 1.4 × 10⁻⁴ 1.6 × 10⁻⁹ 3.0 × 10⁵ ~1.0 × 10⁻⁵   <1 × 10⁻¹⁰ 73D1 1.5 ×10⁵ 2.4 × 10⁻⁴ 1.8 × 10⁻⁹ 4.0 × 10⁵ 3.0 × 10⁻⁵ 7.4 × 10⁻¹⁰ Hz73D1.v1 8.5× 10⁴ 2.5 × 10⁻⁴ 3.0 × 10⁻⁹ 3.6 × 10⁵ 2.7 × 10⁻⁴ 7.5 × 10⁻¹⁰ ¹Bindingassay was performed under low resolution parameters

These results demonstrated that the humanization process for exemplaryanti-ILT2/ILT4 antibodies did not have a significant effect on theantibodies' binding capabilities to human ILT2 or human ILT4.

Cross-reactivity of humanized anti-ILT2/ILT4 antibodies with cynomolgusmonkey (“cyno”, Macaca fascicularis) ILT2 were also assayed. Similar toanti-ILT2/ILT4 antibodies, humanized anti-ILT2/ILT4 antibodies bind tocyno ILT2. Binding affinities of an exemplary clone Hz73D1.v1 measuredby a Biacore system are shown in Table 12. In the Biacore system, ahumanized anti-ILT2/ILT4 antibody was captured on a Protein A chip. ILTproteins were injected at different concentrations into the flow cellsto evaluate kinetic parameters at 25° C. The binding affinity (K_(D)) ofHz73D1.v1 to human ILT2 and ILT4 was determined to be 1.03 and 0.205 nM,respectively. The K_(D) of Hz73D1.v1 to cyno ILT2 was determined to be19.1 nM.

TABLE 12 Species of ILT K_(D) (nM) k_(on) (1/Ms) k_(off) (1/s) HumanILT2 1.03 4.72 × 10⁴  4.85 × 10⁻⁵ Human ILT4 0.205 2.2 × 10⁵  4.6 × 10⁻⁵Cynomolgus monkey ILT2 19.1 3.4 × 10⁶ 0.06

Example 6 ILT2 and ILT4 Expression in Subsets of Immune Cells

ILT2 and ILT4 expression has been described on various cells ofhematopoietic origin, including myeloid cells, granulocytes, andlymphocytes (Colonna M et al. J Exp Med. (1997) December 1; 186(11):1809-1818; Colonna M et al., J Immunol (1998), 160(7): 3096-3100).Anti-ILT antibodies described herein were used to further elucidate theexpression of ILT2 and ILT4 on subsets of human and cyno immune cells.

Flow cytometry analysis of blood immune cells was performed on human andcyno PBMC and whole blood. PBMC were prepared from a leukopak (AllcellsInc.) by centrifugation through ficoll, washing with PBS and freezing incryopreservation buffer in liquid nitrogen until use. Whole blood(Allcells Inc.) was obtained fresh and red blood cells (RBC) depletedusing ammonium chloride RBC lysing solution (Biolegend). PBMC or wholeblood samples were stained with a fluorescently labeled antibody panelto distinguish various immune subsets (monocytes, B cells, NK cells,CD4+and CD8+ T cells, neutrophils and eosinophils). Samples were furtherstained with fluorescently labeled isotype, 27F9 (ILT2 specific), 48A5(ILT4 specific), 73D1, and Hz73D1.v1. The number of ILT2 and ILT4molecules per cell of each immune subset was estimated by incubationwith Quantum Simply Cellular microspheres followed by flow cytometryanalysis.

As shown in Table 13 and FIG. 1, high expression of ILT2 was observed onmonocytes, B cells, a subset of NK cells (5-20% total NK cells), and asubset of CD8+ T cells (5-20% total CD8+ T cells). High expression ofILT4 was observed on monocytes, eosinophils and neutrophils. The resultsshowed that cynomolgus monkey peripheral immune cells express ILT2protein with a level of expression and immune cell distributioncomparable with the combination of ILT2 and ILT4 in human peripheralblood.

TABLE 13 CD8 NK Cell T Cell Antigen Monocyte Neutrophil B Cell (Subset)(Subset) Human ILT2 5.0 × 10⁴ 0 2.0 × 10⁴ 4.0 × 10³ 5.5 × 10³ Human ILT45.0 × 10⁴ 2.5 × 10⁴ 0 0 0 Cynomolgus 1.3 × 10⁵ 5.0 × 10⁴ 2.0 × 10³ 8.0 ×10³ 5.0 × 10³ monkey ILT2

Example 7 Inhibition of the Interaction Between ILT2 or ILT4 and MHC IMolecules by Anti-ILT Antibodies

As part of the characterization process, the ability of exemplaryantibodies to inhibit or block the interaction of ILT2 or ILT4 withtheir natural ligands was evaluated in competition experiments using aBiacore system. As described herein, the natural ligands of ILT2 andILT4 include, but are not limited to, HLA class I molecules, includingHLA-A, HLA-B, HLA-C, HLA-E, and HLA-G. Biotinylated HLA-A*1101 wascaptured in high amounts on a NeutrAvidin chip surface. Antigen-antibodycomplexes were prepared with (i) ILT2-ECD and anti-ILT2 antibody 27F9,anti-ILT4 antibody 48A5, or anti-ILT2/ILT4 antibody Hz73D1.v1 and (ii)ILT4-ECD and anti-ILT2 antibody 27F9, anti-ILT4 antibody 48A5, oranti-ILT2/ILT4 antibody Hz73D1.v1. The antibody concentration of eachantibody was titrated from 0.09-100 nM and the concentration of humanILT2-ECD or ILT4-ECD was kept constant at 20 nM. The complexes weremixed in a 96-well microplate and each was injected onto theHLA-A-coated chip surface. The measured signal (response unit, RU) wasplotted against the antibody concentration.

The results are shown in FIG. 2. A decrease in binding of ILT2 to HLA-Awas observed with increasing concentrations of anti-ILT2 antibody 27F9and anti-ILT2/ILT4 antibody Hz73D1.v1 in a dose-dependent manner. Incontrast, anti-ILT4 antibody 48A5 had no effect on the binding of ILT2to HLA-A. Similarly, a decrease in binding of ILT4 to HLA-A was observedwith increasing concentrations of anti-ILT4 antibody 48A5 andanti-ILT2/ILT4 antibody Hz73D1.v1, with no effect by anti-ILT2 antibody27F9. The antibodies were observed to inhibit the interactions at IC50sin the nanomolar range. Another set of experiments was carried out usinga HLA-G-coated chip surface with similar results.

These data demonstrate that anti-ILT2 and anti-ILT2/ILT4 antibodiesdescribed herein inhibit the interactions between ILT2 and its naturalligands. In addition, anti-ILT4 and anti-ILT2/ILT4 antibodies describedherein inhibit the interactions between ILT4 and its natural ligands.Importantly, this experiment also showed that the anti-ILT2/ILT4antibody not only bound to both targets, i.e., ILT2 and ILT4, but wasbiologically functional in blocking the interactions of both targetswith their ligands. These results show that anti-ILT2/ILT4 antibodiesmay be a potential therapeutic for blocking ILT2-induced andILT4-induced suppression of immune responses.

Example 8 Binding of Anti-ILT2/ILT4 Antibody to Cells

The binding of anti-ILT2/ILT4 antibodies to monocytes was evaluated. Thebinding of exemplary anti-ILT2/ILT4 antibody 73D1 and the humanizedversion Hz73D1.v1 to the CD14+ monocyte population of human and cynoPBMC were determined by flow cytometry analysis. Briefly, human or cynoPBMCs (from 2 donors each) were thawed, washed in media (RPMI, 10% FBS,L-glutamine, pen/strep), and resuspended in fresh media. PBMCs werestained with a cocktail of labeled antibodies to differentiate betweenthe different cell types. 1×10⁶ cells/well were stained withfluorescently-labelled 73D1 or Hz73D1.v1 antibody and incubated on ice.The cells were washed with ice-cold reagents and immediately analyzed byflow cytometry. The geometric mean fluorescence intensity forCD14+monocytes was calculated for each sample. As shown in FIG. 3, anincrease in fluorescence was observed at increasing concentrations ofantibodies 73D1 and Hz73D1.v1 in both human cells and cyno cells.Furthermore, binding of the antibodies to human cells and cyno cells wascomparable. For example, the 50% effective concentration (EC5o) ofHz73D1.v1 was 8.8 nM with human monocytes and 1.8 nM with cynomonocytes. Cells stained with a control antibody showed no shift influorescence. These results demonstrate that anti-ILT2/ILT4 antibodiesrecognize ILT2 and/or ILT4 on intact cells, i.e., primary monocytes.Importantly, these results show that there is comparable binding to bothhuman and cyno monocytes, suggesting that monkeys will be a suitablemodel for future studies. Further, no binding of anti-ILT2/ILT4antibodies described herein was observed to monocytes and other immunecells from rat and mouse, confirming that rodents are not an appropriatespecies for nonclinical testing.

In addition to binding to ILT2 and ILT4, anti-ILT2/ILT4 antibodies showcross-reactivity with LILRA1, but not with ILLRB3, ILLRB4, ILLRB5,ILLRA2, ILLRA4, ILLRA5, and ILLRA6. Binding of anti-ILT2/ILT4 antibodiesto ILT family members was evaluated by fluorescent-activated cellsorting (FACS) using 293T cells expressing human and cynomolgus monkeyILT2, ILT4, LILRA1, ILLRB3, ILLRB4, ILLRB5, ILLRA2, ILLRA4, ILLRA5, andILLRA6 respectively. The binding affinities of an exemplaryanti-ILT2/ILT4 antibody Hz73D1.v1 to human ILT2, human ILT4, humanLILRA1, and cyno LILRA1 expressed on 293T cells and measured by flowcytometry are shown to be 1.2nM, 1.4nM, 2.64nM and 1.97 nM respectively.

Example 9 Inhibition of the Interaction Between ILT2 or ILT4 and MHC IMolecules by Anti-ILT Antibodies

The ability of anti-ILT2/ILT4 antibodies to inhibit the interactionbetween ILT2 and/or ILT4 and MHC I molecules was evaluated using areporter cell system. The Raji cell line was established over 50 yearsago from a Burkitt lymphoma and has been shown to express MHC I and WICII molecules. The lymphoblastoid cell line (LCL) 721.221 is a mutant ofparent LCL 721, wherein LCL 721.221 does not express any MHC Imolecules. LCL 721.221 cells were transfected with the non-classical WICI molecule HLA-G and a stable cell line was established, referred toherein as 721.221-HLA-G. Raji cells or 721.221-HLA-G cells wereco-cultured with cells expressing a stable reporter system and a cellsurface receptor of interest (“reporter cells”). In this chimericreceptor system, the extracellular domain of the receptor of interest(e.g., ILT2 or ILT4) is fused with the transmembrane/intracellulardomain of PILRβ that associates with the adaptor protein DAP12. When thechimeric receptor (e.g., ILT2 or ILT-4) is activated by binding to aligand (e.g., MHC I molecule), DAP12 becomes phosphorylated andactivates an NFAT-responsive promoter which drives GFP expression (see,e.g., Deng et al., 2014, Blood, 124:924-93 5).

ILT2 and ILT4 reporter cells (expressing human ILT2 or human ILT4) werestained with CellTracker Deep Red (ThermoFisher) to distinguish themfrom Raji or 721.221-HLA-G cells upon analysis. Reporter cells werewashed after staining and resuspended at 1×10⁶ cells/ml in X-VIVO™ 15media (Lonza). Raji cells or 721.221-HLA-G cells were washed andresuspended in X-VIVO™ 15 media at 1'10⁶ cell/ml. For assays with Rajicells: anti-ILT2 antibody 27F9, anti-ILT4 antibody 48A5, anti-ILT2/ILT4antibody 73D1 and Hz73D1.v1, and a control antibody were seriallydiluted and 50 μl was added to each well of a 96-well flat-bottom cellculture plate. For assays with 721.221-HLA-G cells: anti-ILT4 antibody48A5, anti-ILT2/ILT4 antibody Hz73D1.v1, and a control antibody wereserially diluted and 50 μl was added to each well of a 96-wellflat-bottom cell culture plate. ILT2-expressing or ILT4-expressingreporter cells (100 μl/well) were co-cultured with Raji cells or721.221-HLA-G cells (100 μl/well). The plates were incubated overnightat 37° C. The next day, reporter cells were assayed for GFP expressionby FACS.

As shown in FIG. 4A, expression of GFP was induced when ILT2 or ILT4 wasexpressed on the surface of the reporter cells in the presence of Rajicells. With reporter cells expressing ILT2 on their cell surface, anincreasing concentration of anti-ILT2 antibody 27F9 and anti-ILT2/ILT4antibody 73D1 or Hz73D1.v1 was observed to inhibit GFP expression in adose-dependent manner (expressed as the % GFP-positive cells). Anti-ILT4antibody was seen to have no inhibitory effect. Similarly, with reportercells expressing ILT4 on their cell surface, an increasing concentrationof anti-ILT4 antibody 48A5 and anti-ILT2/ILT4 antibody 73D1 orHz73D1.v1, was observed to inhibit GFP expression in a dose-dependentmanner and the anti-ILT2 antibody had no effect. As shown in FIG. 4B,expression of GFP was induced when ILT2 or ILT4 was expressed on thesurface of the reporter cells in the presence of 721.221-HLA-G cells.With reporter cells expressing ILT2 on their cell surface, an increasingconcentration of anti-ILT2/ILT4 antibody Hz73D1.v1 was observed toinhibit GFP expression in a dose-dependent manner. With reporter cellsexpressing ILT4 on their cell surface, an increasing concentration ofanti-ILT4 antibody 48A5 and anti-ILT2/ILT4 antibody Hz73D1.v1 wasobserved to inhibit GFP expression in a dose-dependent manner. Table 14shows IC₅₀ of Hz73D1.v1 for blocking the interaction of human ILT2,human ILT4, and cyno ILT2 with MHC I molecules on Raji cells. Table 15shows IC₅₀ of Hz73D1.v1 for blocking the interaction of human ILT2,human ILT4 with HLA-G expressed on 721.221 cells.

TABLE 14 Reporter Construct Raji Cell IC₅₀ (nM) Human ILT2 0.25 HumanILT4 0.066 Cyno ILT2 0.094

TABLE 15 721.221-HLA-G Reporter Construct IC₅₀ (nM) Human ILT2 0.23Human ILT4 0.26

These results show that anti-ILT2 or anti-ILT2/ILT4 antibodies are ableto inhibit and/or block the functional interaction between ILT2 andclassical MHC I molecules to a high level. In parallel, these resultsshow that anti-ILT4 or anti-ILT2/ILT4 antibodies are able to inhibitand/or block the functional interaction between ILT4 and classical andnon-classical MHC I molecules (e.g., HLA-G) to a high level. Theseresults support the idea that an antibody that binds ILT2 and ILT4 wouldmodulate pathways induced by both of these molecules. Therefore, ananti-ILT2/ILT4 antibody may be a stronger therapeutic agent than anantibody that targets only ILT2 or only ILT4.

An additional study was undertaken with reporter cells expressing cynoILT2. As described above, cyno ILT2 reporter cells were stained withCellTracker Deep Red, washed, and resuspended at 1×10⁶ cells/ml inX-VIVO™ 15 media (Lonza). Raji cells were washed and resuspended inX-VIVO™ 15 media at 1×10⁶ cell/ml. Anti-ILT2/ILT4 antibody 73D1 andHz73D1.v1 and a control antibody were serially diluted and 50 μl wasadded to each well of a 96-well flat-bottom cell culture plate.ILT2-expressing reporter cells (100 μl/well) were co-cultured with Rajicells (100 μl/well). The plates were incubated overnight at 37° C. Thenext day, reporter cells were assayed for GFP expression by FACS.

As shown in FIG. 5, expression of GFP was induced when cyno ILT2/4 wasexpressed on the surface of the reporter cells in the presence of Rajicells. In the presence of an increasing concentration of anti-ILT2/ILT4antibody 73D1 or Hz73D1.v1, the percentage of GFP-expressing cells wasdecreased in a dose-dependent manner. Table 14 shows IC₅₀ of Hz73D1.v1for blocking the interaction of cyno ILT2 with MHC I molecules on Rajicells. These results are further evidence that monkeys would be a goodmodel for testing.

In addition to the reporter cell system, the inhibitory activity ofanti-ILT2/ILT4 antibodies towards the interaction between ILT2 and MHC Imolecules, and the interaction between ILT4 and MHC I molecules wasevaluated using the Biacore system. Human ILT2-Fc and ILT4-Fc were usedas target receptors and their interaction with an exemplary MHC-Imolecule (HLA-A) was assayed in the presence or absence of an exemplaryanti-ILT2/ILT4 antibody Hz73D1.v1 at 25° C. Anti-human ILT2 (clone 27F9)or ILT4 (clone 48A5) antibodies were used as tool reagents to dissectILT2- and ILT4-specific blocking activities. Anti-IL2/ILT4 antibodiesproduced a dose-dependent reduction in the interaction between ILT2 andHLA-A, as well as between ILT4 and HLA-A. IC50s of the antibodies testedare shown in Table 16.

TABLE 16 Antibody ILT2 IC₅₀ (nM) ILT4 IC₅₀ (nM) Hz73D1.v1  10 ± 0.36 9.4± 0.34 48A5 (ILT4 specific) No blocking 8.4 ± 0.46 27F9 (ILT2 specific)8.9 ± 0.37 No blocking

Example 10 Effect of Anti-ILT Antibodies on Activity of NK Cells

NKL is a human natural killer (NK) cell line established from theperipheral blood of a patient with large granular lymphocyte (LGL)leukemia and kindly provided by Dr. Louis Lanier. As disclosed herein,NK cells express ILT2 but generally do not express ILT4. 721.221 cellswere transfected with plasmids expressing either HLA-G or HLA-A*0201 andhigh-expressing pools were enriched by antibiotic selection, generating721.221-HLA-G and 721.221-A*0201 cell lines. 721.221-HLA-G cells(described herein) or 721.221-HLA-A*0201 cells are used as targets incytolytic cell assays. The target cells were labeled with CellTrackerDeep Red (ThermoFisher) to distinguish them from NKL cells (afterco-culture) and then resuspended at 5×10⁵ cells/ml in assay media (RPMIwith 10% FBS, penicillin/streptomycin, L-glutamine, 5% human serum andrecombinant human IL-2 (rhIL-2) at 20 ng/ml). NKL cells were suspendedat 7.5×10⁶ cells/ml in assay media. Serial dilutions of anti-ILT2antibody 27F9, anti-ILT4 antibody 48A5, anti-ILT2/ILT4 antibodies 73D1or Hz73D1.v1, and a control isotype antibody were prepared in assaymedia and 50 μl was added to wells of a V-bottom 96-well plate. NKLcells (50 μl) were added to each well, followed by target cells (50 μl),resulting in a target to NK ratio of 1:15. Plates were cultured for 3.5hours at 37° C. followed by centrifugation at 360×g for 8 minutes atroom temperature and removal of media. Cells were then resuspended inPBS containing a 1:1,000 dilution of Sytox Blue (ThermoFisher). SytoxBlue will stain cells with compromised cell membranes allowing livecells to be distinguished from dead or damaged cells. Cells wereanalyzed by FACS and the percent target cell killing was calculatedbased on the value of a positive control well of target cellspermeabilized with detergent (100% lysis).

As shown in FIG. 6, anti-ILT2 antibody 27F9 and anti-ILT2/ILT4antibodies 73D1 and Hz73D1.v1 enhanced NK cytolytic activity in adose-dependent manner. EC₅₀ values for Hz73D1.v1 were 2.4 nM for HLA-Gexpressing target cells and 0.13 nM for HLA-A*0201 expressing targetcells. In comparison, EC₅₀ for 27F9 was 0.064 nM for HLA-G expressingtarget cells. Anti-ILT4 antibody 48A5 had little to no effect on NK cellactivity. These results show that anti-ILT2 antibodies andanti-ILT2/ILT4 antibodies are able to block the functional interactionbetween ILT2 on NK cells and MHC I molecules on the surface of targetcells, leading to the enhancement of cytolytic activity. This supportsthe theory that anti-ILT2/ILT4 antibodies could enhance killing of tumorcells by inhibiting ILT2-induced suppression of NK cells.

Similar experiments were undertaken using human primary NK cells.Briefly, NK cells were isolated from PBMC by negative selection, washedin assay media (RPMI with 10% FBS, pen/strep, 5% human serum, rhIL-2 (40ng/ml), and IL-15 (50 ng/ml)), and resuspended at 7.5×10⁶ cells/ml inassay media. 721.221-HLA-G target cells were labeled with CellTrackerDeep Red (ThermoFisher) and resuspended at 5×10⁵ cells/ml in assaymedia. Target cells and NK cells (50 μl each) were combined in each wellof a V-bottom plate. Anti-ILT2 antibody 27F9, anti-ILT4 antibody 48A5,or anti-ILT2/ILT4 antibodies 47H6, 73D1, or 64A12 were added to wells ata final concentration of 1 μg/ml. Plates were cultured overnight at 37°C. followed by centrifugation at 360×g for 8 minutes at room temperatureand removal of media. Cells were then resuspended in PBS containing a1:1,000 dilution of Sytox Blue (ThermoFisher). Cells were analyzed byFACS and the percent target cell killing was calculated based on thevalue of a positive control well of target cells permeabilized withdetergent (100% lysis).

As shown in FIG. 7, the presence of anti-ILT2 antibody 27F9 oranti-ILT2/ILT4 antibodies 47H6, 73D1, and 64A12, enhanced killing byprimary NK cells. In agreement with other experiments described herein,these results show that ILT2 mediates suppression of primary NK cellsand this suppression can be reversed with antagonist antibodiesinhibiting or blocking ILT2/MHC I interactions.

Further experiments were performed to evaluate NK cell cytolyticactivity via analysis of CD137 expression, a marker that is upregulatedon NK cells during cytolysis. NK cells were isolated from PBMC andcultured with a K562 cell line transfected to express the non-classicalMHC-I molecule HLA-G. NK cell cytolytic activity was evaluated by FACSanalysis of expression of activation marker CD137, gating on the CD3negative, CD56 positive NK population. CD57 staining was performed toenrich for memory (adaptive) NK cells known to preferentially expressILT2 (Lopez-Vergès S et al, Proc.Natl. Acad. Sci. (2011), 108 (36)14725-14732). CD137 is upregulated on NK cells during cytolysis,providing a surrogate measure of cell killing. Hz73D1.v1 or anti-ILT2(27F9), but not anti-ILT4 (48A5), significantly increased the CD137+population (FIG. 8). This effect was most pronounced in the CD57+ memoryNK cell population. These data suggest that anti-IL2/ILT4 antibodies areable to block the interaction of ILT2 on primary NK cells with MHC-I ontarget cells, leading to enhanced activation and cytolytic activity.

To evaluate activity of anti-IL2/ILT4 antibodies on killing of targetcells naturally expressing HLA-A/B/C (classic MHC-I), an antibodydependent cellular cytotoxicity (ADCC) assay was performed. NK cellswere isolated from PBMC and cultured with the CAL-27 squamous cellcarcinoma cell line which expresses high levels of HLA-A, HLA-B, HLA-Cand the NKG2A ligand HLA-E (data not shown). Anti-EGFR antibody wasadded to induce ADCC of these EGFR+ CAL-27 cells. CD137 was upregulatedon NK cells during cytolysis, providing a surrogate measure of cellkilling. Hz73D1.v1 or anti-ILT2 27F9, but not anti-ILT4 48A5,significantly increased the percent CD137+ NK cells in the CD57+population (FIG. 9). By comparison, an anti-NKG2A antibody significantlyincreased percent CD137+ in the CD57−, but not the CD57+ population.Both antibodies induced a comparable fold increase in activation(Hz73D1.v1 increased percent CD137+ cells 1.8-fold while anti-NKG2Aantibody increased percent CD137+ cells 2.1-fold). An anti-KIR2DLantibody showed no activity in this assay. These data suggest thatanti-ILT2/ILT4 antibodies are able to block the interaction of ILT2 onprimary NK cells with classic MHC-I on target cells, leading to enhancedactivation and cytolytic activity of NK cells.

Example 11 Effect of Anti-ILT Antibodies on MDSC Activity in MLR Assay

Myeloid-derived suppressor cells (MDSC) have been shown to be criticalin regulating immune responses by suppressing antigen presenting cells(APC) and T-cells. Furthermore, they have been observed to have anegative effect on anti-tumor activity by immune cells. The effect ofanti-ILT antibodies on MDSC activity was investigated using a mixedlymphocyte reaction assay (MLR). To generate MDSC-like cells, humanperipheral monocytes were grown in pre-conditioned X-VIVO™ 15 media(Lonza). Pre-conditioned media is generated by culture with the OVISEcell line. The OVISE cell line is an ovarian clear cell adenocarcinomawhich secretes a large number of factors into its growth media.Monocytes were cultured in media consisting of 50% OVISE-conditionedmedia and 50% fresh X-VIVO™ 15 for 5 days; the resulting MDSC-like cellsare referred to as ovMDSCs. These MDSC-like cells show MDSC functionalcharacteristics, including increased Arg1 and IDO and suppression of Tcell proliferation and pro-inflammatory cytokines in MLR (MixedLymphocyte Reaction) assays when compared to monocyte derived dendriticcells (data not shown). As a positive control for the assays,monocyte-derived dendritic cells (moDC) were generated by culture ofhuman peripheral monocytes with GM-CSF and IL-4 for 5 days. To performthe MLR assay, 1×10⁵ allogeneic T-cells were co-cultured with 2.5×10⁴ovMDSCs or moDCs in a 96-well round bottom cell culture plate. The cellswere co-cultured in the presence of anti-ILT2 antibody 27F9, anti-ILT4antibody 48A5, anti-ILT2/ILT4 antibodies 47H6 or 73D1, or an isotypecontrol antibody (each at 10 μg/ml). Controls included T-cells only,moDCs only, moDCs with T-cells (positive MLR), ovMDSCs only, and ovMDSCswith T-cells. Cells were incubated at 37° C. and after 5 days 50 μl ofmedia containing ³H-Thymidine was added to each well. After 18 hours ofincubation, the cells from each well were harvested and analyzed forthymidine incorporation as a marker for proliferation, and thesupernatants were analyzed for cytokine secretion by multiplex beadarray.

As shown in FIG. 10, T-cell proliferation was suppressed by co-culturewith ovMDSCs. The presence of anti-ILT4 antibody 48A5 and anti-ILT2/ILT4antibodies 47H6 and 73D1 increased proliferation of T-cells culturedwith ovMDSC to a level equivalent to the MLR response of T-cells withmoDCs. Anti-ILT2 antibody 27F9 showed no ability to enhance T-cellproliferation.

Another MLR assay was set up wherein 1×10⁵ allogeneic T-cells wereco-cultured with 2.5×10⁴ ovMDSCs in a 96-well round bottom cell cultureplate. The cells were co-cultured in the presence of serial dilutions ofanti-ILT2 antibody 27F9, anti-ILT4 antibody 48A5, anti-ILT2/ILT4antibodies 73D1 or Hz73D1.v1, or a control isotype antibody. Cells wereincubated at 37° C. and after 5 days 50 μl of supernatant was harvestedfrom each well for cytokine analysis using a Luminex system.Subsequently, 50 μl of media containing ³H-Thymidine was added to eachwell. After 18 hours of incubation, the cells from each well wereharvested and analyzed for thymidine incorporation.

Similar to results described above, anti-ILT4 antibody 48A5 andanti-ILT2/ILT4 antibodies 73D1 and Hz73D1.v1 were shown to increaseT-cell proliferation (FIG. 11A). In addition, it was determined thatTNF-α secretion and GM-CSF secretion were increased in a dose-dependentmanner in the presence of anti-ILT4 and anti-ILT2/ILT4 antibodies (FIG.11B-11C). As in the previous experiment, no effect was seen withanti-ILT2 antibodies.

These results show that anti-ILT4 and anti-ILT2/ILT4 antibodies are ableto inhibit and/or block the functional interaction between ILT4 on MDSCsand MHC I molecules on neighboring cells (e.g., APCs), leading to thereversal of MDSC suppression and the enhancement of T-cell activation.The reversal of MDSC-induced suppression also appears to lead to theincreased secretion of pro-inflammatory cytokines such as TNF-α andGM-CSF.

Example 12 Effect of Anti-ILT2/4 Antibodies on LPS-Mediated Stimulationof Cells

Lipopolysaccharide (LPS) stimulates innate immune responses on myeloidcells via toll-like receptors 2 and 4 (TLR2 and TLR4). To determinewhether anti-ILT2 and/or anti-ILT4 antibodies can enhance LPS-mediatedstimulation, a PBMC/LPS assay was performed. Briefly, frozen human PBMCswere thawed, washed in media (RPMI with 10% FBS, L-glutamine andpen/strep) and counted. Anti-ILT2 antibody 27F9, anti-ILT4 antibody48A5, anti-ILT2/ILT4 antibodies 73D1 and Hz73D1.v1, and a controlisotype antibody were serially diluted in media and 50 μl added to eachwell of a 96-well round bottom tissue culture plate. PBMCs were added at1×10⁶ cells/ml in a volume of 100 μl and the plate was incubated at 37°C. for 30 minutes. LPS was added in 50 μl of media (final concentrationof 30 ng/ml) and the plate were incubated at 37° C. for 2 days. Cellsupernatants were removed for analysis of cytokines using a Luminex®system.

As shown in FIG. 12, the presence of anti-ILT4 and anti-ILT2/ILT4antibodies resulted in the increased production of GM-CSF and TNFα in adose-dependent manner. For example, the EC₅₀ values of Hz73D1.v1 were0.76 nM for TNFα secretion and 1.5 nM for GM-CSF secretion. Anti-ILT2antibody 27F9 and the control antibody showed little GM-CSF and TNFαsecretion (approximately 20-40 pg/ml). These results show that theexpression of ILT4 on myeloid cells in the PBMC culture can stronglysuppress the production of pro-inflammatory cytokines induced by LPS,and importantly, that the suppression can be reversed by inhibitingand/or blocking ILT4/MHC I interactions.

A similar experiment was set up using cyno PMBCs. Briefly, cyno PBMCswere washed in media (RPMI with 10% FBS, L-glutamine and pen/strep) andcounted. Anti-ILT2/ILT4 antibody Hz73D1.v1 or a control antibody wasserially diluted in media and 50 μl added to each well of a 96-wellround bottom tissue culture plate. PMBCs were added at 2×10⁶ cells/ml in100 μl and plates were incubated at 37° C. for 30 minutes. LPS was addedin 50 μl of media (final concentration of 50 ng/ml) and plates wereincubated at 37° C. for 2 days. Cell supernatants were removed foranalysis of cytokines using a Luminex® system.

Similar to the results with human PBMCs, anti-ILT2/4 antibody Hz73D1.v1enhanced GM-CSF secretion from cyno PBMCs (FIG. 13). EC₅₀ was determinedto be 14 nM. These results show that anti-ILT2/ILT4 antibodies had asimilar biological effect on cyno immune cells and human immune cells.

To further evaluate the effect of anti-ILT antibodies on cells involvedin suppression of immune responses to tumor cells, a LPS assay withtolerogenic dendritic cells (tolDC) was set up. Briefly, isolated humanmonocytes were plated onto 10 cm tissue culture dishes at 4×10⁶cells/dish in a volume of 20 ml media (X-VIVO™ 15 media (Lonza)supplemented with 50 ng/mL each of recombinant GM-CSF and IL-4(Peprotech)). The monocytes were incubated for 5-7 days at 37° C. andthen the cells were harvested. For the assay, the in vitro generated DCswere suspended in fresh media containing 1:50 dilution of Fc Block(Biolegend) at a concentration of 6×10⁵ cells/ml. DCs were seeded in96-well tissue culture plates at 50 μl/well and anti-ILT4 antibody 48A5,anti-ILT2/ILT4 antibody Hz73D1.v1, or a control antibody were added inserial dilutions at 50 μl/well. LPS was added (6 μg/ml finalconcentration) together with one of a variety of tolerizing agents in avolume of 50 λl media. The tolerizing agents included: vitaminD3/dexamethasone (VitD3/Dex) at 100 nM and 10 nM respectively,cyclosporin A at 750 ng/ml, rapamycin at 100 ng/ml, prostaglandin E2(PGE2) at 1 μg/ml, IL-6 at 20 ng/ml, IL-10 at 20 ng/ml or TGFα at 20ng/ml. Plates were incubated at 37° C. for 2 days and supernatants wereharvested for analysis using a Luminex® system.

As shown in FIG. 14, anti-ILT4 and anti-ILT2/ILT4 antibodies enhancedLPS-mediated cytokine (e.g., TNFα) secretion in a dose-dependent manner.The EC50 values of Hz73D1.v1 induced TNFa secretion in the presence ofLPS and an additional tolerizing agent are shown in table 17. Incontrast, there was no increase of TNF-α in tolDCs treated with acontrol antibody and anti-ILT2 antibody (data not shown). These datashow that tolDCs present within a patient's tumor would be responsive toreactivation by the presence of anti-ILT4 and/or anti-ILT2/ILT4antibodies that inhibit or block ILT4 and MHC I molecule interactions.

TABLE 17 Treatment VitD3/Dex PGE2 IL-10 Cyclosporine Rapamycin IL-6 TGFβEC₅₀ (nM) 0.40 0.44 1.2 0.20 0.15 0.14 0.10

Example 13

Effect of Anti-ILT Antibodies on HMGB1, STING and/or Anti-CD3Stimulation of PBMCs

High mobility group protein B1 (HMGB1) is a nuclear protein that can bereleased from cells and binds to TLRs. HMGB1 has been shown to bepresent at high concentrations in necrotic tumor tissue, providing apotential source of innate stimulation of tumor infiltrating DC,monocytes, and macrophages (see, e.g., Guerriero et al., 2011, J.Immunol., 186:3517-3526). Experiments were designed to determine whetheranti-ILT antibodies could enhance pro-inflammatory cytokine secretionfrom PBMCs treated with HMGB1. Briefly, anti-ILT2 antibody 27F9,anti-ILT4 antibody 48A5, anti-ILT2/ILT4 antibodies 47H6, 73D1 and 64A12,and a control isotype antibody were serially diluted in media and 50 μladded to each well of a 96-well round bottom tissue culture plate. PBMCswere added at 1×10⁶ cells/ml in a volume of 100 μl and the plate wasincubated at 37° C. for 30 minutes. Recombinant HMGB1 (Biolegend) wasadded at a concentration of 2.5 μg/ml (a concentration anticipated to bepresent in the microenvironment of a tumor) and the plate was incubatedat 37° C. for 2 days. Cell supernatants were removed for analysis ofcytokines using a Luminex® system.

As shown in FIG. 15, anti-ILT4 antibody 48A5 and anti-ILT2/ILT4antibodies 47H6, 73D1, and 64A12 enhanced secretion of TNF-α. These datashow that anti-ILT4 and anti-ILT2/ILT4 antibodies will enhance thepro-inflammatory function of infiltrating monocytes within a tumor.

Similarly, tumor cell necrosis and/or tumor cell death from radiotherapyresults in the release of nuclear DNA. Free nuclear DNA can lead tomyeloid cell stimulation via STING (stimulator of interferon genes)signaling. Experiments were designed to determine whether anti-ILTantibodies could enhance inflammatory cytokine production from PBMCstreated with a STING agonist. Briefly, PBMCs were plated in 96-wellround bottom tissue culture plates and anti-ILT2 antibody 27F9,anti-ILT4 antibody 48A5, and a control isotype antibody were added.After a 30-minute incubation, STING agonist 2′3′-cGAMP (Invivogen) wasadded at a concentration of 10 μg/ml (a concentration anticipated to bepresent in the microenvironment of a necrotic tumor). Cells wereincubated for two days and supernatants were analyzed using a Luminex®system.

As shown in FIG. 16, exemplary anti-ILT4 antibody 48A5 enhancedsecretion of IFNγ, TNF-α, and IL-1β. These data show that anti-ILT4 andanti-ILT2/ILT4 antibodies will enhance the pro-inflammatory functions oftumor infiltrating monocytes.

In addition to suppression of innate immune activators, ILT2 or ILT4 mayplay a role in suppression of T-cell-mediated stimulation of myeloidcells. To evaluate T-cell stimulation of myeloid cells, PBMCs wereactivated with an anti-CD3 antibody and recombinant IL-2. Briefly,anti-ILT2 antibody 27F9, anti-ILT4 antibody 48A5, anti-ILT2/ILT4antibodies 47H6 and 64A12, and a control isotype antibody were seriallydiluted in media and 50 μl added to each well of a 96-well round bottomtissue culture plate. PBMCs were added at 1×10⁶ cells/ml in a volume of100 μl and the plate was incubated at 37° C. for 30 minutes. Anti-CD3antibody clone HIT3a (eBioscience) was added at a concentration of 10ng/ml and recombinant IL-2 was added at a concentration of 100 U/ml(Peprotech). Cells were incubated for two days and supernatants wereanalyzed using a Luminex® system.

As shown in FIG. 17, anti-ILT4 antibody 48A5 and anti-ILT2/ILT4antibodies 47H6 and 64A12 enhanced TNF-α secretion in a dose-dependentmanner. Anti-ILT2 antibody 27F9 did not have any effect of cytokineproduction. These data show that ILT4 blockade enhances the immuneresponse (i.e., pro-inflammatory cytokine secretion) resulting frominteraction between activated T-cells and myeloid cells.

Example 14 Effect of Anti-ILT Antibodies on Macrophage Phagocytosis

Phagocytosis assays were performed to further characterize the effect ofanti-ILT2, anti-ILT4, and anti-ILT2/ILT4 antibodies on macrophagefunctions. Macrophages were generated by culture of isolated monocytesin media (RPMI with 10% FBS, L-glutamine and pen/strep) containing 50ng/ml recombinant M-CSF (Peprotech) for 5 days at 37° C. in 12-welltissue culture plates. Macrophages were removed from the plate with acell scraper and plated at 20,000 cells/well in 100 μl media in a flatbottom 96-well tissue culture plate. Macrophages were incubatedovernight at 37° C. The next day, antibody was added to the macrophagesat a concentration of 2.5 μg/ml together with 2.5 μg/ml of anti-CD47antibody to induce antibody dependent phagocytosis. Raji cells werestained for 1 hour with a 1:4,000 dilution of pH Rodo Red Dye (EssenBioscience), washed in media and added at 50,000 cells/well tomacrophages. Phagocytosis was measured by mean red fluorescence on anIncucyte machine at 45 minute intervals. Test antibody was compared toisotype control antibody at the peak response timepoint (3 hours).

As shown in FIG. 18, anti-ILT2/ILT4 antibodies (e.g., Hz73D1.v1) andanti-ILT2 antibodies (e.g., 27F9) enhanced phagocytic activity ofmacrophages against Raji tumor cells opsonized with anti-CD47 antibody.Anti-ILT4 antibodies (e.g., 48A5) had no effect on phagocytosis bymacrophages. To control for ILT2 expression by Raji cells, antibody24E7, an ILT2 binder unable to block MHC-I interaction, was used. Thesedata show that anti-ILT2 and anti-ILT2/ILT4 antibodies are able toenhance macrophage phagocytosis by blocking macrophage ILT2 interactionwith MHC-I on tumor cells, and inhibiting ILT-2 induced suppression ofmacrophages, thus increasing macrophage phagocytosis of tumors. Thisactivity of anti-ILT2 and anti-ILT2/ILT4 antibodies is specific toblocking ILT2/MHC-I interaction but not ILT4/MHC-1 interaction despiteILT4 expression on macrophages.

Example 15 Effect of Anti-ILT Antibodies on Dendritic Cells

It is believed that ILT2 and/or ILT4 act as suppressors of myeloid cellactivation and that inhibition or blocking of ILT2 and/or ILT4 wouldinhibit ILT2 and/or ILT4-induced suppression.

Activation of myeloid cells can be achieved by the crosslinking of Fcreceptors (FcR) on the cell surface and the crosslinking results incytokine production; this is used as the basis for a myeloid cellactivation assay. Dendritic cells were generated as described herein.Briefly, isolated human monocytes were plated on 10 cm tissue culturedishes with 4×10⁶ cells per dish in a volume of 20 ml media (Lonza)supplemented with 50 ng/mL each of recombinant GM-CSF and IL-4(Peprotech). The monocytes were incubated for 5-7 days at 37° C. and theresulting dendritic cells were harvested. Maxisorp 96-well ELISA plateswere coated with anti-KLH antibody (5 μg/mL) and incubated overnight at4° C. The anti-KLH antibody contains an Fc domain capable of binding Fcreceptors on the dendritic cells. The plates were washed and blockedwith X-VIVO™ 15 media for one hour. Dendritic cells were added at 7×10⁴cells/well. Anti-ILT2 antibody 27F9, anti-ILT4 antibody 48A5, acombination of antibodies 27F9 and 48A5, anti-ILT2/ILT4 antibodyHz73D1.v1 or a control antibody were added at serial dilutions andplates incubated at 37° C. for 2 days. Supernatants were collected andanalyzed for TNF-α secretion using a Luminex® system.

As shown in FIG. 19, a combination of anti-ILT2 antibody 27F9 andanti-ILT4 antibody 48A5 and anti-ILT2/ILT4 antibody 73D1 enhanced TNF-αsecretion from dendritic cells in a dose-dependent manner. Anti-ILT2antibody 27F9 as a single agent and anti-ILT4 antibody 48H6 as a singleagent had only a small effect on increasing cytokine production. Thusthe strong increase in cytokine secretion by the combination ofanti-ILT2 antibody 27F9 with anti-ILT4 antibody 48A5 was surprising.This response was mirrored with the dual binding anti-ILT2/ILT4 antibodyHz73D1.v1. These data show that both ILT2 and ILT4 inhibitFc-receptor-mediated activation of dendritic cells and that theseeffects are non-redundant. These data show that inhibiting thesuppression of dendritic cells with agents that target both ILT2 andILT4 (i.e., a dual binding anti-ILT2/ILT4 antibody) may result in a muchbetter therapeutic effect than therapy with mono-specific antibodies.

Example 16

Effect of Anti-ILT Antibodies on Cytokine Secretion from Human and CynoBlood Cells

To investigate the potential for toxicity related to cytokine release(i.e., a “cytokine storm”), a variety of antibodies were cultured withhuman or cyno blood cells and cytokine production was analyzed. Briefly,antibodies were added at 10 μg/ml to 96-well flat-bottom plates andshaken at room temperature for 1 hour. The antibodies tested includedanti-ILT4 antibody 48A5, anti-ILT2/ILT4 antibodies 47H6, 73D1, andHz73D1.v1, superagonist anti-CD28 antibody clone 5D10 (Ancell),polyclonal anti-ILT2 antibody (R&D Systems), polyclonal anti-ILT4antibody (R&D Systems), anti-LILRA1 antibody (R&D Systems), anti-CD3antibody, and a control antibody. Plates were washed and blocked withculture media (RPMI with 10% FBS, L-glutamine and pen/strep) for 1 hourwith shaking. Blood was obtained from healthy human donors and cynomonkeys. Red blood cells were removed from blood by lysis in RBC lysisbuffer (eBioscience), followed by centrifugation, and the remainingcells were washed with culture media. 5×10⁵ cells were added per well,with LPS added to replicate wells as a positive control, and platesincubated at 37° C. for 24 hours. Supernatants were collected andassayed for cytokine secretion using a Luminex® system.

As shown in FIG. 20, incubation of human blood cells with soluble LPS orplate-coated anti-CD28 antibody induced a significant increase in manycytokines including TNF-α, GM-CSF, MIP-1α, IL-6, IL-1β, and IL-10. Incontrast, polyclonal anti-ILT2 antibody, polyclonal anti-ILT4 antibody,anti-LILRA1 antibody, anti-ILT4 antibody 48A5, and anti-ILT2/ILT4antibodies 73D1 and Hz73D1.v1 failed to induce cytokine levels aboveisotype control antibody from the human blood cells. As shown in FIG.21, incubation of cyno blood cells with soluble LPS induced asignificant increase in cytokines such as TNF-α, IL-1β, MIP-1 α, IL-6and MIP-1β. Similar to the human blood cell assay, polyclonal anti-ILT2antibody, polyclonal anti-ILT4 antibody, anti-LILRA1 antibody, anti-CD3antibody, and anti-ILT2/ILT4 antibodies 47H6, 73D1, and Hz73D1.v1 failedto induce cytokine levels above the level seen with the isotype controlantibody from the cyno blood cells. These data show that the potentialof anti-ILT2 antibodies, ILT-4 antibodies, and anti-ILT2/ILT4 antibodiesto produce a toxic immune response, such as a cytokine storm, is low.

A further in vitro cytokine release assay was performed to evaluate thecapacity of anti-ILT2/ILT4 antibodies to induce pro-inflammatorycytokines IL-2, TNF-α, IL-6 and IFN-γ. Whole blood samples for 10healthy donors were used. Anti-ILT2/ILT4 antibodies were compared with anumber of positive and negative controls. An anti-KLH isotype controlantibody was used as a negative control. A super-agonist anti-CD28antibody (clone ANC28.1) was used as a positive control (Walker 2011).In addition, Staphylococcus enterotoxin B (SEB) was used as a positivecontrol for soluble antibody cultures. Two assay formats were used. Inthe first format, cells were cultured with an antibody (Hz73D1.v1, anisotype control antibody or anti-CD28 antibdy) or SEB at increasingconcentrations. Antibodies were tested at 0.1, 1, 10 and 100 μg/ml. SEBwas tested at 0.01, 0.1 and 1 μg/ml. In the second format, 96-welltissue culture plates were pre-incubated with an antibody overnight at4° C., washed and then cells were added and cultured. Cell culturesupernatant was then collected and tested for cytokine levels bycytometric bead array assay.

In the first assay format, SEB at 1 μg/mL induced high levels of allcytokines evaluated (IL-2, IL-6, TNFα and IFNγ), with cytokine levelsabove isotype control for all 10 donors. Soluble anti-CD28 antibody at100 μg/mL induced cytokine levels above isotype control for IL-6, TNFαand IFNγ. Median values with Hz73D1.v1 were comparable with the isotypecontrol (Table 18). In the second assay format, the positive control ofplate-coated anti-CD28 (100 μg/ml) induced IL-6 in 5 of 10 donors. Incontrast, plate-coated Hz73D1.v1 did not induce any of the 4 cytokinesto a level above that of isotype control (Table 19).

TABLE 18 Anti-CD28 (μg/mL) SEB (μg/mL) Isotype (μg/mL) Hz73D1.v1 (μg/mL)10 100 0.1 1 10 100 10 100 IL-6 1115 8934 571 1422 7 5 3 6 IL-2 44 481309 3418 19 21 17 20 TNFα 52 605 614 1452 4 7 6 10 IFNγ 35 343 208 7045 6 5 5

TABLE 19 Anti-CD28 (μg/mL) Isotype (μg/mL) Hz73D1.v1 (μg/mL) 10 100 10100 10 100 IL-6 17 93 10 9 9 7 IL-2 33 45 40 38 28 32 TNFα 18 26 17 1916 12 IFNγ 12 21 13 13 12 14

Example 17 Effect of Anti-ILT Antibodies on T Cell Activity

ILT2 expression is known to be enriched on a population of effectormemory CD45RA+ CD8+ T cells (CD8+ T EMRA cells) (Gustafson 2017). Thispopulation is only a small proportion of CD8+ T cells in healthy donors,making bulk CD8+ T cell cell-killing assays challenging. Therefore, tocharacterize the cytolytic activity of ILT2+ CD8 T cells, primary CD8+ Tcells were transduced with ILT2 and expanded in vitro to generatesufficient numbers of ILT2+ CD8+ T cells. Cytolytic activity was thenevaluated in a CD8+ T cell killing assay using fluorescently labeled721.221-HLA-G target cells. Briefly, frozen PBMC were thawed, washed inmedia (RPMI with 10% FBS, L-glutamine and pen/strep) and CD8+ T cellswere isolated using a CD8+ T cell positive selection kit. Isolated CD8+T cells were cultured in basic media (Xvivo15 media with 10 mM HEPES, 2mM Glutamine, pen/strep and 5% normal human serum) and stimulated for 24hours at 37° C. with CD3/28 beads adding 5 μl beads per million cells.Activated T cells (2×10⁵) were then harvested and resuspended in 1 ml ofLentivirus expressing human ILT2 at a viral concentration of 1×10⁷PFU/ml in the presence of polybrene to infect cells. Infected cells werethen resuspended in T cell media (basic media supplemented with 5 ng/mlIL-7, 5 ng/ml IL-15 and 25 ng/ml IL-2) and allowed to expand for twoweeks. Cells were then FACS sorted for the ILT2+ population and expandedfor an additional 6 weeks to generated sufficient cells for the study.For evaluation of cytolytic activity, 2.5×10⁴ CellTracker deepred-labelled 721.221-HLAG cells were mixed with 2.5×10⁵ ILT2-transducedCD8+ T cells at a 10:1 T cell:Target ratio and 0.1 μg/ml anti-CD3/CD19bispecific antibody in RPMI-10% FBS media. Anti-ILT antibodies orcontrol antibodies were added to the cells at a concentration of 10μg/ml and incubated for 18 hours. Target cells were analyzed by FACS andpercent target cell killing was calculated as the number of dead targetcells divided by the total number of target cells.

As shown in FIG. 22, anti-ILT2/ILT4 antibodies (e.g., Hz73D1.v1) andanti-ILT2 antibodies (e.g., 27F9), but not anti-ILT4 antibodies (e.g.,48A5), enhanced cytolytic activity of CD8+ T cells against 721.221-HLA-Gtarget cells. These data show that anti-ILT2 and anti-ILT2/ILT4antibodies enhance CD8+ T cell cytolytic activity by blocking CD8+ Tcell ILT2 interaction with MHC-I on target cells. As such, anti-ILT2 andanti-ILT2/ILT4 antibodies disrupt the immune suppressive activity ofILT2 on cytolytic lymphocytes, in particular effector memory T cellsknown to be involved in anti-tumor cell killing.

Example 18 Synergistic Effect of Anti-ILT2/ILT4 Antibodies and Anti-PD1Antibodies on T Cell Activity

A mixed leukocyte reaction assay was developed to evaluate potentialsynergistic or additive effects of anti-ILT2/ILT4 antibodies incombination with an anti-PD1 antibody (Pembrolizumab). Monocyte derivedmacrophages were generated and cultured with allogeneic CD4+ T cellsfrom 11 different donors, together with either isotype control,Hz73D1.v1, Pembrolizumab, or the combination of Hz73D1.v1 andPembrolizumab. Briefly, monocyte derived macrophages were generated byculturing 100,000 monocytes per well for 6 days with 50 ng/mlrecombinant M-CSF. On day 6, allogeneic purified CD4+ T cells(200,000/well) were added together with either 1 μg/ml anti-KLH isotypecontrol, 1 μg/ml Pembrolizumab, 1 μg/ml Hz73D1.v1, or the combination ofanti-PD1 and Hz73D1.v1 at 1 g/ml each. Cells were cultured for anadditional 6 days and supernatant collected for multiplex bead arrayanalysis on secreted cytokines (IFN-γ, TNF-α, and GM-CSF).

As shown in FIG. 23A-23C, the anti-ILT2/ILT4 antibody or Pembrolizumabalone typically induced <2 ng/ml of interferon gamma in cultures, with 3out of 11 donors inducing >2 ng/ml interferon gamma. In contrast, thecombination of the anti-ILT2/ILT4 antibody and Pembrolizumab induced >2ng/ml interferon gamma in 7 out of 11 CD4+ T cell donor pairs, with agreater-than-additive response compared to each reagent alone in these 7donor pairs. Similar responses were observed with GM-CSF and TNF-αsecretion. These data shows that the anti-ILT2/ILT4 antibody andpembrolizumab together have a synergistic effect on allogeneic CD4+ Tcell induced cytokine secretion, possibly through a combination ofanti-ILT2/ILT4 antibody-mediated stimulation of macrophage APC activityand the release of CD4+ T cell checkpoint inhibition by Pembrolizumab.Altogether, an anti-ILT2/ILT4 antibody or anti-PD-1 antibody alonemodestly enhance T cell activation and increase in cytokine secretion.Combination of an anti-ILT2/ILT4 antibody or anti-PD-1 antibody leads tosynergetic increase in T cell activation and cytokine secretion.

Example 19 Anti-ILT2/ILT4 Antibodies Induce M2-Like to M1-LikePolarization of Monocyte-Derived Macrophages

Macrophages are traditionally characterized as either pro-inflammatory(M1) or immune suppressive (M2) based on surface expression markersCD80, CD86 (M1), CD163, CD204, and CD206 (M2). Anti-IL2/ILT4 antibodiesas well as anti-IL2 and anti-ILT4 antibodies were evaluated for theirability to polarize macrophages toward an M1-like or M2-like phenotype.

Macrophages were generated by culture of monocytes in media (RPMI with10% FBS, L-glutamine and pen/strep) containing Hz73D1.v1, 27F9, 48A5 orisotype control antibody (1 ug/ml) and 50 ng/ml recombinant M-CSF(Peprotech) for 5 days at 37° C. in 48-well tissue culture plates. Onday 5 samples were analyzed by flow cytometry for various surfacemarkers indicative of an M1-like or M2-like phenotype.

As shown in FIG. 24, Hz73D1.v1 induced a decrease in M2-like macrophagephenotypic markers CD163, CD204, and CD206 and additional M2-likemarkers CD14 and CD209, consistent with an M2-like to M1-likepolarization of the monocytes during differentiation. Anti-ILT4 specificantibody 48A5, but not anti-ILT2 specific antibody 27F9, induced anincrease in M1-like marker CD86 and a decrease in M2-like markers CD163,CD204, and CD206, and additional M2-like markers CD14, CD209, and CCRS,consistent with an M2-like to M1-like polarization with ILT4 blockade.Overall, these data demonstrate that anti-ILT2/ILT4 antibodies induce amore pro-inflammatory M1-like phenotype during macrophagedifferentiation, and this response is mediated by inhibition of ILT4interaction with MHC-I.

Although the foregoing present disclosure has been described in somedetail by way of illustration and example for purposes of clarity ofunderstanding, the descriptions and examples should not be construed aslimiting the scope of the present disclosure. The embodiments of thepresent disclosure described herein are intended to be merely exemplary,and those skilled in the art will recognize numerous equivalents to thespecific procedures described herein. All such equivalents areconsidered to be within the scope of the present disclosure and arecovered by the embodiments.

All publications, patents, patent applications, internet sites, andaccession numbers/database sequences including both polynucleotide andpolypeptide sequences cited herein are hereby incorporated by referencein their entirety for all purposes to the same extent as if eachindividual publication, patent, patent application, internet site, oraccession number/database sequence were specifically and individuallyindicated to be so incorporated by reference.

Following are sequences disclosed in the application. CDR sequences arelisted in

Tables 1-8.

Human ILT2 amino acid sequence with predicted signal sequence underlined(SEQ ID NO: 1)MTPILTVLICLGLSLGPRTHVQAGHLPKPTLWAEPGSVITQGSPVTLRCQGGQETQEYRLYREKKTALWITRIPQELVKKGQFPIPSITWEHAGRYRCYYGSDTAGRSESSDPLELVVTGAYIKPTLSAQPSPVVNSGGNVILQCDSQVAFDGFSLCKEGEDEHPQCLNSQPHARGSSRAIFSVGPVSPSRRWWYRCYAYDSNSPYEWSLPSDLLELLVLGVSKKPSLSVQPGPIVAPEETLTLQCGSDAGYNRFVLYKDGERDFLQLAGAQPQAGLSQANFTLGPVSRSYGGQYRCYGAHNLSSEWSAPSDPLDILIAGQFYDRVSLSVQPGPTVASGENVTLLCQSQGWMQTFLLTKEGAADDPWRLRSTYQSQKYQAEFPMGPVTSAHAGTYRCYGSQSSKPYLLTHPSDPLELVVSGPSGGPSSPTTGPTSTSGPEDQPLTPTGSDPQSGLGRHLGVVIGILVAVILLLLLLLLLFLILRHRRQGKHWTSTQRKADFQHPAGAVGPEPTDRGLQWRSSPAADAQEENLYAAVKHTQPEDGVEMDTRSPHDEDPQAVTYAEVKHSRPRREMASPPSPLSGEFLDTKDRQAEEDRQMDTEAAASEAPQDVTYAQLHSLTLRREATEPPPSQEGPSPAVPSIYATLAIHHuman ILT2 amino acid sequence without predicted signal sequence(SEQ ID NO: 2)GHLPKPTLWAEPGSVITQGSPVTLRCQGGQETQEYRLYREKKTALWITRIPQELVKKGQFPIPSITWEHAGRYRCYYGSDTAGRSESSDPLELVVTGAYIKPTLSAQPSPVVNSGGNVILQCDSQVAFDGFSLCKEGEDEHPQCLNSQPHARGSSRAIFSVGPVSPSRRWWYRCYAYDSNSPYEWSLPSDLLELLVLGVSKKPSLSVQPGPIVAPEETLTLQCGSDAGYNRFVLYKDGERDFLQLAGAQPQAGLSQANFTLGPVSRSYGGQYRCYGAHNLSSEWSAPSDPLDILIAGQFYDRVSLSVQPGPTVASGENVTLLCQSQGWMQTFLLTKEGAADDPWRLRSTYQSQKYQAEFPMGPVTSAHAGTYRCYGSQSSKPYLLTHPSDPLELVVSGPSGGPSSPTTGPTSTSGPEDQPLTPTGSDPQSGLGRHLGVVIGILVAVILLLLLLLLLFLILRHRRQGKHWTSTQRKADFQHPAGAVGPEPTDRGLQWRSSPAADAQEENLYAAVKHTQPEDGVEMDTRSPHDEDPQAVTYAEVKHSRPRREMASPPSPLSGEFLDTKDRQAEEDRQMDTEAAASEAPQDVTYAQLHSLTLRREATEPPPSQEGPSPAVPSIYATLAIH Human ILT2 extracellular domain (aa 24-461)(SEQ ID NO: 3)GHLPKPTLWAEPGSVITQGSPVTLRCQGGQETQEYRLYREKKTALWITRIPQELVKKGQFPIPSITWEHAGRYRCYYGSDTAGRSESSDPLELVVTGAYIKPTLSAQPSPVVNSGGNVILQCDSQVAFDGFSLCKEGEDEHPQCLNSQPHARGSSRAIFSVGPVSPSRRWWYRCYAYDSNSPYEWSLPSDLLELLVLGVSKKPSLSVQPGPIVAPEETLTLQCGSDAGYNRFVLYKDGERDFLQLAGAQPQAGLSQANFTLGPVSRSYGGQYRCYGAHNLSSEWSAPSDPLDILIAGQFYDRVSLSVQPGPTVASGENVTLLCQSQGWMQTFLLTKEGAADDPWRLRSTYQSQKYQAEFPMGPVTSAHAGTYRCYGSQSSKPYLLTHPSDPLELVVSGPSGGPSSPTTGPTSTSGPEDQPLTPTGSDPQSGLGRHLGVHuman ILT2 Ig-like C2-type domain 1 amino acid sequence (aa 27-115)(SEQ ID NO: 4)PKPTLWAEPGSVITQGSPVTLRCQGGQETQEYRLYREKKTALWITRIPQELVKKGQFPIPSITWEHAGRYRCYYGSDTAGRSESSDPLEHuman ILT2 Ig-like C2-type domain 2 amino acid sequence (aa 116-221)(SEQ ID NO: 5)LVVTGAYIKPTLSAQPSPVVNSGGNVILQCDSQVAFDGFSLCKEGEDEHPQCLNSQPHARGSSRAIFSVGPVSPSRRWWYRCYAYDSNSPYEWSLPSDLLELLVLGHuman ILT2 Ig-like C2-type domain 3 amino acid sequence (aa 222-312)(SEQ ID NO: 6)VSKKPSLSVQPGPIVAPEETLTLQCGSDAGYNRFVLYKDGERDFLQLAGAQPQAGLSQANFTLGPVSRSYGGQYRCYGAHNLSSEWSAPSDHuman ILT2 Ig-like C2-type domain 4 amino acid sequence (aa 313-409)(SEQ ID NO: 7)PLDILIAGQFYDRVSLSVQPGPTVASGENVTLLCQSQGWMQTFLLTKEGAADDPWRLRSTYQSQKYQAEFPMGPVTSAHAGTYRCYGSQSSKPYLLTHuman ILT4 amino acid sequence with predicted signal sequence underlined(SEQ ID NO: 8)MTPIVTVLICLGLSLGPRTHVQTGTIPKPTLWAEPDSVITQGSPVTLSCQGSLEAQEYRLYREKKSASWITRIRPELVKNGQFHIPSITWEHTGRYGCQYYSRARWSELSDPLVLVMTGAYPKPTLSAQPSPVVTSGGRVTLQCESQVAFGGFILCKEGEEEHPQCLNSQPHARGSSRAIFSVGPVSPNRRWSHRCYGYDLNSPYVWSSPSDLLELLVPGVSKKPSLSVQPGPVVAPGESLTLQCVSDVGYDRFVLYKEGERDLRQLPGRQPQAGLSQANFTLGPVSRSYGGQYRCYGAHNLSSECSAPSDPLDILITGQIRGTPFISVQPGPTVASGENVTLLCQSWRQFHTFLLTKAGAADAPLRLRSIHEYPKYQAEFPMSPVTSAHAGTYRCYGSLNSDPYLLSHPSEPLELVVSGPSMGSSPPPTGPISTPAGPEDQPLTPTGSDPQSGLGRHLGVVIGILVAVVLLLLLLLLLFLILRHRRQGKHWTSTQRKADFQHPAGAVGPEPTDRGLQWRSSPAADAQEENLYAAVKDTQPEDGVEMDTRAAASEAPQDVTYAQLHSLTLRRKATEPPPSQEREPPAEPSIYATLAIHHuman ILT4 amino acid sequence without predicted signal sequence(SEQ ID NO: 9)QTGTIPKPTLWAEPDSVITQGSPVTLSCQGSLEAQEYRLYREKKSASWITRIRPELVKNGQFHIPSITWEHTGRYGCQYYSRARWSELSDPLVLVMTGAYPKPTLSAQPSPVVTSGGRVTLQCESQVAFGGFILCKEGEEEHPQCLNSQPHARGSSRAIFSVGPVSPNRRWSHRCYGYDLNSPYVWSSPSDLLELLVPGVSKKPSLSVQPGPVVAPGESLTLQCVSDVGYDRFVLYKEGERDLRQLPGRQPQAGLSQANFTLGPVSRSYGGQYRCYGAHNLSSECSAPSDPLDILITGQIRGTPFISVQPGPTVASGENVTLLCQSWRQFHTFLLTKAGAADAPLRLRSIHEYPKYQAEFPMSPVTSAHAGTYRCYGSLNSDPYLLSHPSEPLELVVSGPSMGSSPPPTGPISTPAGPEDQPLTPTGSDPQSGLGRHLGVVIGILVAVVLLLLLLLLLFLILRHRRQGKHWTSTQRKADFQHPAGAVGPEPTDRGLQWRSSPAADAQEENLYAAVKDTQPEDGVEMDTRAAASEAPQDVTYAQLHSLTLRRKATEPPPSQEREPPAEPSIYATLAIHHuman ILT4 extracellular domain (aa 22-461) (SEQ ID NO: 10)QTGTIPKPTLWAEPDSVITQGSPVTLSCQGSLEAQEYRLYREKKSASWITRIRPELVKNGQFHIPSITWEHTGRYGCQYYSRARWSELSDPLVLVMTGAYPKPTLSAQPSPVVTSGGRVTLQCESQVAFGGFILCKEGEEEHPQCLNSQPHARGSSRAIFSVGPVSPNRRWSHRCYGYDLNSPYVWSSPSDLLELLVPGVSKKPSLSVQPGPVVAPGESLTLQCVSDVGYDRFVLYKEGERDLRQLPGRQPQAGLSQANFTLGPVSRSYGGQYRCYGAHNLSSECSAPSDPLDILITGQIRGTPFISVQPGPTVASGENVTLLCQSWRQFHTFLLTKAGAADAPLRLRSIHEYPKYQAEFPMSPVTSAHAGTYRCYGSLNSDPYLLSHPSEPLELVVSGPSMGSSPPPTGPISTPAGPEDQPLTPTGSDPQSGLGRHLGVHuman ILT4 Ig-like C2-type domain 1 amino acid sequence (aa 27-110)(SEQ ID NO: 11)PKPTLWAEPDSVITQGSPVTLSCQGSLEAQEYRLYREKKSASWITRIRPELVKNGQFHIPSITWEHTGRYGCQYYSRARWSELSHuman ILT4 Ig-like C2-type domain 2 amino acid sequence (aa 111-229)(SEQ ID NO: 12)DPLVLVMTGAYPKPTLSAQPSPVVTSGGRVTLQCESQVAFGGFILCKEGEEEHPQCLNSQPHARGSSRAIFSVGPVSPNRRWSHRCYGYDLNSPYVWSSPSDLLELLVPGVSKKPSLSVHuman ILT4 Ig-like C2-type domain 3 amino acid sequence (aa 230-318)(SEQ ID NO: 13)QPGPVVAPGESLTLQCVSDVGYDRFVLYKEGERDLRQLPGRQPQAGLSQANFTLGPVSRSYGGQYRCYGAHNLSSECSAPSDPLDILITHuman ILT4 Ig-like C2-type domain 4 amino acid sequence (aa 330-419)(SEQ ID NO: 14)QPGPTVASGENVTLLCQSWRQFHTFLLTKAGAADAPLRLRSIHEYPKYQAEFPMSPVTSAHAGTYRCYGSLNSDPYLLSHPSEPLELVVSRhesus ILT2 amino acid sequence with predicted signal sequence underlined(SEQ ID NO: 15)MTPILMVLICLGLSLGSRTRVQAGTFPKPTLWAEPGSMISKGSPVTLRCQGSLPVQDYRLQREKKTASWVRRIQQELVKKGYFPIASITSEHAGQYRCQYYSHSWWSEPSDPLELVVTGAYSKPTLSALPSPVVASGGNVTLQCDSQVAXGGFVLCKEGEDEHPQCLNSQPHTRGSSRAVFSVGPVSPSRRWSYRCYGYDSRSPYVWSLPSDLLELLVPGVSKKPSLSVQPGPVVAPGDKLTLQCGSDAGYNRFALYKEGERDFLQRPGRQPQAGLSQANFLLDPVRRSHGGQYRCSGAHNLSSEWSAPSDPLDILIAGQIRGRPSLLVQPGPTVVSGENVTLLCQSSWQFHVFLLTQAGAADAHLHLRSMYKYPKYQAEFPMSPVTSAHAGTYRCYGSHSSDSYLLSIPSDPLELVVSGPSGGPSSPTTGPTSTCGPEDQPLTPTGSDPQSGLGRHLGVVTGVLVAFVLLLFLLLLLFLVLRHRRQGKRWTSAQRKADFQHPAGAVEPEPRDRGLQRRSSPAANTQEENLYAAVKDTQPEDGVELDSRSPHDEDPQAVTYARVKHSRPRREMASPPSPLSEEFLDTKDTQAAASEDPQDVTYAQLQSLTLRRETTEPPPSQEREPPVESSIYATLTIHRhesus ILT2 amino acid sequence without predicted signal sequence(SEQ ID NO: 16)GTFPKPTLWAEPGSMISKGSPVTLRCQGSLPVQDYRLQREKKTASWVRRIQQELVKKGYFPIASITSEHAGQYRCQYYSHSWWSEPSDPLELVVTGAYSKPTLSALPSPVVASGGNVTLQCDSQVAXGGFVLCKEGEDEHPQCLNSQPHTRGSSRAVFSVGPVSPSRRWSYRCYGYDSRSPYVWSLPSDLLELLVPGVSKKPSLSVQPGPVVAPGDKLTLQCGSDAGYNRFALYKEGERDFLQRPGRQPQAGLSQANFLLDPVRRSHGGQYRCSGAHNLSSEWSAPSDPLDILIAGQIRGRPSLLVQPGPTVVSGENVTLLCQSSWQFHVFLLTQAGAADAHLHLRSMYKYPKYQAEFPMSPVTSAHAGTYRCYGSHSSDSYLLSIPSDPLELVVSGPSGGPSSPTTGPTSTCGPEDQPLTPTGSDPQSGLGRHLGVVTGVLVAFVLLLFLLLLLFLVLRHRRQGKRWTSAQRKADFQHPAGAVEPEPRDRGLQRRSSPAANTQEENLYAAVKDTQPEDGVELDSRSPHDEDPQAVTYARVKHSRPRREMASPPSPLSEEFLDTKDTQAAASEDPQDVTYAQLQSLTLRRETTEPPPSQEREPPVESSIYATLTIH Rhesus ILT2 extracellular domain (aa 24-460)(SEQ ID NO: 17)GTFPKPTLWAEPGSMISKGSPVTLRCQGSLPVQDYRLQREKKTASWVRRIQQELVKKGYFPIASITSEHAGQYRCQYYSHSWWSEPSDPLELVVTGAYSKPTLSALPSPVVASGGNVTLQCDSQVAXGGFVLCKEGEDEHPQCLNSQPHTRGSSRAVFSVGPVSPSRRWSYRCYGYDSRSPYVWSLPSDLLELLVPGVSKKPSLSVQPGPVVAPGDKLTLQCGSDAGYNRFALYKEGERDFLQRPGRQPQAGLSQANFLLDPVRRSHGGQYRCSGAHNLSSEWSAPSDPLDILIAGQIRGRPSLLVQPGPTVVSGENVTLLCQSSWQFHVFLLTQAGAADAHLHLRSMYKYPKYQAEFPMSPVTSAHAGTYRCYGSHSSDSYLLSIPSDPLELVVSGPSGGPSSPTTGPTSTCGPEDQPLTPTGSDPQSGLGRHLGVRhesus ILT2 Ig-like C2-type domain 1 amino acid sequence (aa 27-114)(SEQ ID NO: 18)PKPTLWAEPGSMISKGSPVTLRCQGSLPVQDYRLQREKKTASWVRRIQQELVKKGYFPIASITSEHAGQYRCQYYSHSWWSEPSDPLERhesus ILT2 Ig-like C2-type domain 2 amino acid sequence n (aa 115-220)(SEQ ID NO: 19)LVVTGAYSKPTLSALPSPVVASGGNVTLQCDSQVAXGGFVLCKEGEDEHPQCLNSQPHTRGSSRAVFSVGPVSPSRRWSYRCYGYDSRSPYVWSLPSDLLELLVPGRhesus ILT2 Ig-like C2-type domain 3 amino acid sequence n (aa 221-311)(SEQ ID NO: 20)VSKKPSLSVQPGPVVAPGDKLTLQCGSDAGYNRFALYKEGERDFLQRPGRQPQAGLSQANFLLDPVRRSHGGQYRCSGAHNLSSEWSAPSDRhesus ILT2 Ig-like C2-type domain 4 amino acid sequence n (aa 312-408)(SEQ ID NO: 21)PLDILIAGQIRGRPSLLVQPGPTVVSGENVTLLCQSSWQFHVFLLTQAGAADAHLHLRSMYKYPKYQAEFPMSPVTSAHAGTYRCYGSHSSDSYLLS27F9 Heavy chain variable region amino acid sequence (SEQ ID NO: 125)QVQLKESGPGLVAPSQSLSITCTVSGFSLTNYGVSWVRQPPGKGLEWLGIIWGDGSTNYHSALISRLSISKDNSKSQVFLKLNSLQADDTATYYCAKPNWDTYAMDFWGQGTSVTVSS27F9 Light chain variable region amino acid sequence (SEQ ID NO: 126)DIQMTQTTSSLSASLGDRVTISCRASQDISNFLNWYQQKPDGTVKLLIYCTSKLHSGVPSRFSGSGSETDYSLTISNLEQEDIATYFCQQGNTLPPTFGGGTKLEII47C8 Heavy chain variable region amino acid sequence (SEQ ID NO: 127)EVQLQQSGPDLVKPGASVKISCKASGYSFTGYYMHWVKQSHGKSLEWIGRVYPNNGDTSYNQKFKVKAILTVDKSSSTAYMELRSLTSEDSAVYYCARGATVVESLFAYWGQGTLVTVSA47C8 Light chain variable region amino acid sequence (SEQ ID NO: 128)DIVLTQSPASLAVSLGQRATISCRASESVDNYGNNFLHWYQQKPGQPPKWYRTSNLESGIPARFSGSGSRTDFTLTINPVEADDVATYYCQQSNEDPYTFGGGTKLEIK48A5 Heavy chain variable region amino acid sequence (SEQ ID NO: 129)QIQLVQSGPELKKPGETVKISCKASGYTFTNYGMNWVKQAPGKGLKWMGWINTYIGEPIYADDFKGRFAFSLETSASTAYLQINNLKNEDMATYFCARRSDYDGYAMDYWGQGTSVTVSS48A5 Light chain variable region amino acid sequence (SEQ ID NO: 130)DIVMSQSPSSLAVSVGERVTMSCKSSQSLLYSGNQKNYLAWYQQKPGQSPKLLIYWASTRESGVPDRFTGSGSGTDFTLTISSVKAEDLAVYYCQQHDSYPTFGGGSRLEIK47H6 Heavy chain variable region amino acid sequence (SEQ ID NO: 131)EVQLQQSGPELVKPGASVKISCKASGYTFTDYYMNWVKQSHGKSLEWIGDFNPNNGGTTYNQKFEGKATLTVDKSSNTAYMDLRSLTSEDSAVYYCARGRFYYGSLYSFDYWGQGTTLTVSS47H6 Light chain variable region amino acid sequence (SEQ ID NO: 132)DIQMTQSPASLSASVGETVTITCRASGNIHNYLAWYQQKQGKSPHLLVYNAKTLADGVPSRFSGSGSGTQYSLKINNLQPEDFGSYYCQHFWTSITFGAGTKLDLKHz47H6.v2 Heavy chain variable region amino acid sequence(SEQ ID NO: 133)QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYYMNWVRQAPGQRLEWIGDFNPNNAGTTYNQKFEGRVTITVDKSASTAYMELSSLRSEDTAVYYCARGRFYYGSLYSFDYWGQGTLVTVSSHz47H6.v2 Light chain variable region amino acid sequence(SEQ ID NO: 134)DIQMTQSPSSLSASVGDRVTITCRASGNIHNYLAWYQQKPGKAPKWYNAKTLADGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQHFWTSITFGPGTKVDIK51A1 Heavy chain variable region amino acid sequence (SEQ ID NO: 135)EVQLVESGGGLVQPKGSLKLSCAASGFTFNTYAMHWVRQAPGKGLEWVARIRSKSSNYATYYADSVKDRFTISRDDSQSMLYLQMNNLKTEDTAMYYCVRDGIYYYGTMYYYAMDYWGQG TSVIVSS51A1 Light chain variable region amino acid sequence (SEQ ID NO: 136)NIVLTQSPASLAVSILGQRATISCRASESVDYYGNSFMYWYQQKPGQPPKWYFASNILESGVPARFSGSGSRTDFTLTIDPVEAADAASYYCQQNNEDPWTFGGGTKLEIK64Al2 Heavy chain variable region amino acid sequence (SEQ ID NO: 137)EVQLVESGGGLVQPKGSLKLSCAASGFTFNTYAMHWVRQAPGKGLEWVARIRSKSSNYATYYADSVKDRFTISRDDSQSMLYLQMNNLKTEDTAMYYCVRDGIYYYDTMYYYAMDYWGQG TSVTVSS64Al2 Light chain variable region amino acid sequence (SEQ ID NO: 138)NIVLTQSPASLAVSLGQRATISCRASESVDYYGNSFIYWYQQKPGQPPKWYFASNLESGVPARFSGSGSRTDFTLTIDPVEAADAASYYCQQNNEDPWTFGGGTKLEIKHeavy chain variable region amino acid sequence (SEQ ID NO: 139)EVQLVESGGGLVQPGGSLRLSCAASGFTFNTYAMHWVRQAPGKGLEWVARIRSKSSNYATYYADSVKDRFTISRDDAKNSLYLQMNSLRAEDTAVYYCARDGIYYYDTMYYYAMDYWGQG TLVTVSSHz64Al2 Light chain variable region amino acid sequence (SEQ ID NO: 140)NIVLTQSPDSLAVSLGERATINCRASESVDYYGNSFIYWYQQKPGQPPKWYFASNLESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQQNNEDPWTFGGGTKVEIK73C4 Heavy chain variable region amino acid sequence (SEQ ID NO: 141)AVQLQQSGPELVKPGASVKISCKASGYTFTDYYMNWVKQSHGKSLEWIGNVNPNNGGTSYNQKFKGKATLTVDKSSSTAYMELRSLTSEDSAVYYCARREIYFYGTIYYYAMDYWGQGTS VTVSS73C4 and 73D1 Light chain variable region amino acid sequence(SEQ ID NO: 142)DIVLTQSPASLAVSLGQRATISCRASESVDYYGNSFMYWYQQKPGRPPNLLIYFASNLESGVPARFSGSGSRTDFTLTIDPVEADDAATYYCQQNNEDPWTFGGGTKLEIK73D1 Heavy chain variable region amino acid sequence (SEQ ID NO: 143)AVQLQQSGPELVKPGASVKISCKASGYTFTDYYINWVKQSHGKSLQWIGNVNPNDGGTTYNQKFKGKATLTVDKSSSTAYMELRSLTSEDSAVYYCARREIYFYGTIYYYAMDYWGQGTS VTVSSHz73D1.v1 Heavy chain variable region amino acid sequence(SEQ ID NO: 144)QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYYINWVRQAPGQGLEWMGNVNPNDGGTTYNQKFKGRVTMTTDTSTSTAYMELRSLRSDDTAVYYCARREIYFYGTIYYYAMDYWGQGTL VTVSSHz73D1.v1 Light chain variable region amino acid sequence(SEQ ID NO: 145)DIQLTQSPSFLSASVGDRVTITCRASESVDYYGNSFMYWYQQKPGKAPKWYFASNLESGVPSRFSGSGSGTEFTLTISSLQPEDFATYYCQQNNEDPWTFGGGTKVEIKHz47H6.v2 Heavy chain amino acid sequence with signal sequence underlined(SEQ ID NO: 146)MDMRVPAQLLGLLLLWLRGARCQVQLVQSGAEVKKPGASVKVSCKASGYTFTDYYMNWVRQAPGQRLEWIGDFNPNNAGTTYNQKFEGRVTITVDKSASTAYMELSSLRSEDTAVYYCARGRFYYGSLYSFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYGSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKHz47H6.v2 Light chain amino acid sequence with signal sequence underlined(SEQ ID NO: 147)MDMRVPAQLLGLLLLWLRGARCDIQMTQSPSSLSASVGDRVTITCRASGNIHNYLAWYQQKPGKAPKWYNAKTLADGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQHFWTSITFGPGTKVDIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGECHz47H6.v2 Heavy chain amino acid sequence without signal sequence(SEQ ID NO: 148)QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYYMNWVRQAPGQRLEWIGDFNPNNAGTTYNQKFEGRVTITVDKSASTAYMELSSLRSEDTAVYYCARGRFYYGSLYSFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYGSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKHz47H6.v2 Light chain amino acid sequence without signal sequence(SEQ ID NO: 149)DIQMTQSPSSLSASVGDRVTITCRASGNIHNYLAWYQQKPGKAPKWYNAKTLADGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQHFWTSITFGPGTKVDIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGECHz64A12 Heavy chain amino acid sequence with signal sequence underlined(SEQ ID NO: 150)MDMRVPAQLLGLLLLWLRGARCEVQLVESGGGLVQPGGSLRLSCAASGFTFNTYAMHWVRQAPGKGLEWVARIRSKSSNYATYYADSVKDRFTISRDDAKNSLYLQMNSLRAEDTAVYYCARDGIYYYDTMYYYAMDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYGSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKHz64A12 Light chain amino acid sequence with signal sequence underlined(SEQ ID NO: 151)MDMRVPAQLLGLLLLWLRGARCNIVLTQSPDSLAVSLGERATINCRASESVDYYGNSFIYWYQQKPGQPPKLLIYFASNLESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQQNNEDPWTFGGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGECHz64A12 Heavy chain amino acid sequence without signal sequence(SEQ ID NO: 152)EVQLVESGGGLVQPGGSLRLSCAASGFTFNTYAMHWVRQAPGKGLEWVARIRSKSSNYATYYADSVKDRFTISRDDAKNSLYLQMNSLRAEDTAVYYCARDGIYYYDTMYYYAMDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYGSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKHz64A12 Light chain amino acid sequence without signal sequence(SEQ ID NO: 153)NIVLTQSPDSLAVSLGERATINCRASESVDYYGNSFIYWYQQKPGQPPKWYFASNLESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQQNNEDPWTFGGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGECHz73D1.v1 Heavy chain amino acid sequence with signal sequence underlined(SEQ ID NO: 154)MDMRVPAQLLGLLLLWLRGARCQVQLVQSGAEVKKPGASVKVSCKASGYTFTDYYINWVRQAPGQGLEWMGNVNPNDGGTTYNQKFKGRVTMTTDTSTSTAYMELRSLRSDDTAVYYCARREIYFYGTIYYYAMDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYGSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKHz73D1.v1 Light chain amino acid sequence with signal sequence underlined(SEQ ID NO: 155)MDMRVPAQLLGLLLLWLRGARCDIQLTQSPSFLSASVGDRVTITCRASESVDYYGNSFMYWYQQKPGKAPKWYFASNLESGVPSRFSGSGSGTEFTLTISSLQPEDFATYYCQQNNEDPWTFGGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGECHz73D1.v1 Heavy chain amino acid sequence without signal sequence(SEQ ID NO: 156)QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYYINWVRQAPGQGLEWMGNVNPNDGGTTYNQKFKGRVTMTTDTSTSTAYMELRSLRSDDTAVYYCARREIYFYGTIYYYAMDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYGSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKHz73D1.v1 Light chain amino acid sequence without signal sequence(SEQ ID NO: 157)DIQLTQSPSFLSASVGDRVTITCRASESVDYYGNSFMYWYQQKPGKAPKWYFASNLESGVPSRFSGSGSGTEFTLTISSLQPEDFATYYCQQNNEDPWTFGGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC Human IgG1 constant region (SEQ ID NO: 158)ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK Human IgG1 constant region E233A/L235A (SEQ ID NO: 159)ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPALAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK Human IgG1 constant region L234A/L235A (SEQ ID NO: 160)ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKHuman IgG1 constant region L234A/L235A/P329G  (SEQ ID NO: 161)ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALGAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK Human IgG1 constant region N297G (SEQ ID NO: 162)ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYGSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK Human IgG1 constant region N297G/H310A (SEQ ID NO: 163)ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYGSTYRVVSVLTVLAQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK Human Kappa light chain constant region (SEQ ID NO: 164)RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGECHuman Lambda light chain constant region  (SEQ ID NO: 165)GQPKAAPSVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADSSPVKAGVETTTPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVTHEGSTVEKTVAPTECSCyno ILT2 amino acid sequence with predicted signal sequence underlined(SEQ ID NO: 166)MTPILMVLICLGLSLGPRTHVQAGILPKPTLWAEPGSMISEGSPVTLRCQGSLQVQEYRLYREKKPASWVRRIQQELVKKGYFAIGFITWEHTGQYRCQYYSHSWWSEPSDPLELVVTGAYSKPTLSALPSPVVASGGNVTLQCDSQVAFDSFTLCKEGEDEHPQRLNCQSHARGWSWAVFSVGPVSPSRRWSYRCYGYISSAPNVWSLPSDLLELLVPGVSKKPSLSVQPGPVVAPGDKLTLQCGSDAGYDRFALYKEGEGDFLQRPVRQPQAGLSQANFLLGPVSRSHGGQYRCSGAHNLSSEWSAPSDPLDILIAGQIRGRPFLSVQPGPKVVSGENVTLLCQSSWQFHAFLLTQAGAADAHLHLRSMYKYPKYQAEFPMSPVTSAHAGTYRCYGSRSSNPYLLSVPSDPLELVVSGPSGGPSSPTTGPTSTCAGPEDQPLTPTGSDPQSGLGRHLGVVTGILVAFVLLLFLLLLLFLVLRHQRQGKHWTSAQRKADFQHPAGAVEPEPRDRGLQRRSSPAADTQEENLYAAVKDTQPEDGVELDSRQRPHDEDPQAVTYARVKHSRPRREMASPPSPLSEEFLDTKDTQAEEDRQMDTEAAASEDPQDVTYAQLQSLTLRRETTEPPPSQERAPPVESSIYATLTIHCyno ILT2 amino acid sequence without predicted signal sequence(SEQ ID NO: 167)GILPKPTLWAEPGSMISEGSPVTLRCQGSLQVQEYRLYREKKPASWVRRIQQELVKKGYFAIGFITWEHTGQYRCQYYSHSWWSEPSDPLELVVTGAYSKPTLSALPSPVVASGGNVTLQCDSQVAFDSFTLCKEGEDEHPQRLNCQSHARGWSWAVFSVGPVSPSRRWSYRCYGYISSAPNVWSLPSDLLELLVPGVSKKPSLSVQPGPVVAPGDKLTLQCGSDAGYDRFALYKEGEGDFLQRPVRQPQAGLSQANFLLGPVSRSHGGQYRCSGAHNLSSEWSAPSDPLDILIAGQIRGRPFLSVQPGPKVVSGENVTLLCQSSWQFHAFLLTQAGAADAHLHLRSMYKYPKYQAEFPMSPVTSAHAGTYRCYGSRSSNPYLLSVPSDPLELVVSGPSGGPSSPTTGPTSTCAGPEDQPLTPTGSDPQSGLGRHLGVVTGILVAFVLLLFLLLLLFLVLRHQRQGKHWTSAQRKADFQHPAGAVEPEPRDRGLQRRSSPAADTQEENLYAAVKDTQPEDGVELDSRQRPHDEDPQAVTYARVKHSRPRREMASPPSPLSEEFLDTKDTQAEEDRQMDTEAAASEDPQDVTYAQLQSLTLRRETTEPPPSQERAPPVESSIYATLTIH Cyno ILT2 extracellular domain (aa 24-461) (SEQ ID NO: 168)GILPKPTLWAEPGSMISEGSPVTLRCQGSLQVQEYRLYREKKPASWVRRIQQELVKKGYFAIGFITWEHTGQYRCQYYSHSWWSEPSDPLELVVTGAYSKPTLSALPSPVVASGGNVTLQCDSQVAFDSFTLCKEGEDEHPQRLNCQSHARGWSWAVFSVGPVSPSRRWSYRCYGYISSAPNVWSLPSDLLELLVPGVSKKPSLSVQPGPVVAPGDKLTLQCGSDAGYDRFALYKEGEGDFLQRPVRQPQAGLSQANFLLGPVSRSHGGQYRCSGAHNLSSEWSAPSDPLDILIAGQIRGRPFLSVQPGPKVVSGENVTLLCQSSWQFHAFLLTQAGAADAHLHLRSMYKYPKYQAEFPMSPVTSAHAGTYRCYGSRSSNPYLLSVPSDPLELVVSGPSGGPSSPTTGPTSTCAGPEDQPLTPTGSDPQSGLGRHLGVCyno ILT2 Ig-like C2-type domain 1 amino acid sequence (aa 27-114)(SEQ ID NO: 169)PKPTLWAEPGSMISEGSPVTLRCQGSLQVQEYRLYREKKPASWVRRIQQELVKKGYFAIGFITWEHTGQYRCQYYSHSWWSEPSDPLECyno ILT2 Ig-like C2-type domain 2 amino acid sequence n (aa 115-220)(SEQ ID NO: 170)LVVTGAYSKPTLSALPSPVVASGGNVTLQCDSQVAFDSFTLCKEGEDEHPQRLNCQSHARGWSWAVFSVGPVSPSRRWSYRCYGYISSAPNVWSLPSDLLELLVPGCyno ILT2 Ig-like C2-type domain 3 amino acid sequence n (aa 221-311)(SEQ ID NO: 171)VSKKPSLSVQPGPVVAPGDKLTLQCGSDAGYDRFALYKEGEGDFLQRPVRQPQAGLSQANFLLGPVSRSHGGQYRCSGAHNLSSEWSAPSDCyno ILT2 Ig-like C2-type domain 4 amino acid sequence n (aa 312-408)(SEQ ID NO: 172)PLDILIAGQIRGRPFLSVQPGPKVVSGENVTLLCQSSWQFHAFLLTQAGAADAHLHLRSMYKYPKYQAEFPMSPVTSAHAGTYRCYGSRSSNPYLLS Hexahistidine peptide tag(SEQ ID NO: 173) HHHHHH

1.-81. (canceled)
 82. A binding agent comprising an antigen-bindingdomain, wherein the antigen binding domain binds specifically to bothhuman immunoglobulin-like transcript 2 (ILT2) and humanimmunoglobulin-like transcript 4 (ILT4), wherein the antigen-bindingdomain comprises: (1) a heavy chain variable region (VH) comprising aVH-complementarity determining region (CDR)1, a VH-CDR2, and a VH-CDR3from the amino acid sequence of SEQ ID NO:144; and a light chainvariable region (VL) comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 fromthe amino acid sequence of SEQ ID NO:145; (2) a VH comprising a VH-CDR1,a VH-CDR2, and a VH-CDR3 from the amino acid sequence of SEQ ID NO:139;and a VL comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 from the aminoacid sequence of SEQ ID NO:140; (3) a VH comprising a VH-CDR1, aVH-CDR2, and a VH-CDR3 from the amino acid sequence of SEQ ID NO:133;and a VL comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 from the aminoacid sequence of SEQ ID NO:134; (4) a VH comprising a VH-CDR1, aVH-CDR2, and a VH-CDR3 from the amino acid sequence of SEQ ID NO:143;and a VL comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 from the aminoacid sequence of SEQ ID NO:142; (5) a VH comprising a VH-CDR1, aVH-CDR2, and a VH-CDR3 from the amino acid sequence of SEQ ID NO:131;and a VL comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 from the aminoacid sequence of SEQ ID NO:132; (6) a VH comprising a VH-CDR1, aVH-CDR2, and a VH-CDR3 from the amino acid sequence of SEQ ID NO:137;and a VL comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 from the aminoacid sequence of SEQ ID NO:138; (7) a VH comprising a VH-CDR1, aVH-CDR2, and a VH-CDR3 from the amino acid sequence of SEQ ID NO:135;and a VL comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 from the aminoacid sequence of SEQ ID NO:136; or (8) a VH comprising a VH-CDR1, aVH-CDR2, and a VH-CDR3 from the amino acid sequence of SEQ ID NO:141;and a VL comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 from the aminoacid sequence of SEQ ID NO:142.
 83. The binding agent of claim 82,wherein: (i) (1) the VH comprises the VH-CDR1 comprising the amino acidsequence of SEQ ID NO:115, the VH-CDR2 comprising the amino acidsequence of SEQ ID NO:112, and the VH-CDR3 comprising the amino acidsequence of SEQ ID NO:107; and the VL comprises the VL-CDR1 comprisingthe amino acid sequence of SEQ ID NO:89, the VL-CDR2 comprising theamino acid sequence of SEQ ID NO:90, and the VL-CDR3 comprising theamino acid sequence of SEQ ID NO:91; (2) the VH comprises the VH-CDR1comprising the amino acid sequence of SEQ ID NO:111, the VH-CDR2comprising the amino acid sequence of SEQ ID NO:112, and the VH-CDR3comprising the amino acid sequence of SEQ ID NO:107; and the VLcomprises the VL-CDR1 comprising the amino acid sequence of SEQ IDNO:89, the VL-CDR2 comprising the amino acid sequence of SEQ ID NO:90,and the VL-CDR3 comprising the amino acid sequence of SEQ ID NO:91; (3)the VH comprises the VH-CDR1 comprising the amino acid sequence of SEQID NO:76, the VH-CDR2 comprising the amino acid sequence of SEQ IDNO:113, and the VH-CDR3 comprising the amino acid sequence of SEQ IDNO:107; and the VL comprises the VL-CDR1 comprising the amino acidsequence of SEQ ID NO:89, the VL-CDR2 comprising the amino acid sequenceof SEQ ID NO:90, and the VL-CDR3 comprising the amino acid sequence ofSEQ ID NO:91; (4) the VH comprises the VH-CDR1 comprising the amino acidsequence of SEQ ID NO:111, the VH-CDR2 comprising the amino acidsequence of SEQ ID NO:114, and the VH-CDR3 comprising the amino acidsequence of SEQ ID NO:107; and the VL comprises the VL-CDR1 comprisingthe amino acid sequence of SEQ ID NO:89, the VL-CDR2 comprising theamino acid sequence of SEQ ID NO:90, and the VL-CDR3 comprising theamino acid sequence of SEQ ID NO:91; or (5) the VH comprises the VH-CDR1comprising the amino acid sequence of SEQ ID NO:116, the VH-CDR2comprising the amino acid sequence of SEQ ID NO:124, and the VH-CDR3comprising the amino acid sequence of SEQ ID NO:110; and the VLcomprises the VL-CDR1 comprising the amino acid sequence of SEQ IDNO:99, the VL-CDR2 comprising the amino acid sequence of SEQ ID NO:100,and the VL-CDR3 comprising the amino acid sequence of SEQ ID NO:101;(ii) the VH comprises VH-CDR1, VH-CDR2, and VH-CDR3, and the VLcomprises VL-CDR1, VL-CDR2, and VL-CDR3 comprising amino acid sequencesset out in any one of the five CDR definitions set forth in Table 6B;(iii) the VH comprises VH-CDR1, VH-CDR2, and VH-CDR3, and the VLcomprises VL-CDR1, VL-CDR2, and VL-CDR3 comprising amino acid sequencesset out in any one of the five CDR definitions set forth in Table 4B;(iv) the VH comprises VH-CDR1, VH-CDR2, and VH-CDR3, and the VLcomprises VL-CDR1, VL-CDR2, and VL-CDR3 comprising amino acid sequencesset out in any one of the five CDR definitions set forth in Table 8A;(v) the VH comprises VH-CDR1, VH-CDR2, and VH-CDR3, and the VL comprisesVL-CDR1, VL-CDR2, and VL-CDR3 comprising amino acid sequences set out inany one of the five CDR definitions set forth in Table 4A; (vi) the VHcomprises VH-CDR1, VH-CDR2, and VH-CDR3, and the VL comprises VL-CDR1,VL-CDR2, and VL-CDR3 comprising amino acid sequences set out in any oneof the five CDR definitions set forth in Table 6A; (vii) the VHcomprises VH-CDR1, VH-CDR2, and VH-CDR3, and the VL comprises VL-CDR1,VL-CDR2, and VL-CDR3 comprising amino acid sequences set out in any oneof the five CDR definitions set forth in Table 5; or (viii) the VHcomprises VH-CDR1, VH-CDR2, and VH-CDR3, and the VL comprises VL-CDR1,VL-CDR2, and VL-CDR3 comprising amino acid sequences set out in any oneof the five CDR definitions set forth in Table
 7. 84. The binding agentof claim 82, wherein: (i) (a) the VH has at least 80% sequence identityto the amino acid sequence of SEQ ID NO:144 and/or the VL has at least80% sequence identity to the amino acid sequence of SEQ ID NO:145; (b)the VH has at least 80% sequence identity to the amino acid sequence ofSEQ ID NO:139, and/or the VL has at least 80% sequence identity to theamino acid sequence of SEQ ID NO:140; (c) the VH has at least 80%sequence identity to the amino acid sequence of SEQ ID NO:133, and/orthe VL has at least 80% sequence identity to the amino acid sequence ofSEQ ID NO:134; (d) the VH has at least 80% sequence identity to theamino acid sequence of SEQ ID NO:143, and/or the VL has at least 80%sequence identity to the amino acid sequence of SEQ ID NO:142; (e) theVH has at least 80% sequence identity to the amino acid sequence of SEQID NO:131, and/or the VL has at least 80% sequence identity to the aminoacid sequence of SEQ ID NO:132; (f) the VH has at least 80% sequenceidentity to the amino acid sequence of SEQ ID NO:137, and/or the VL hasat least 80% sequence identity to the amino acid sequence of SEQ IDNO:138; (g) the VH has at least 80% sequence identity to the amino acidsequence of SEQ ID NO:135, and/or the VL has at least 80% sequenceidentity to the amino acid sequence of SEQ ID NO:136; or (h) the VH hasat least 80% sequence identity to the amino acid sequence of SEQ IDNO:141, and/or the VL has at least 80% sequence identity to the aminoacid sequence of SEQ ID NO:142; or (ii) (a) the VH comprises the aminoacid sequence of SEQ ID NO:144 and/or the VL comprises the amino acidsequence of SEQ ID NO:145; (b) the VH comprises the amino acid sequenceof SEQ ID NO:139 and/or the VL comprises the amino acid sequence of SEQID NO:140; (c) the VH comprises the amino acid sequence of SEQ ID NO:133and/or the VL comprises the amino acid sequence of SEQ ID NO:134; (d)the VH comprises the amino acid sequence of SEQ ID NO:143 and/or the VLcomprises the amino acid sequence of SEQ ID NO:142; (e) the VH comprisesthe amino acid sequence of SEQ ID NO:131 and/or the VL comprises theamino acid sequence of SEQ ID NO:132; (f) the VH comprises the aminoacid sequence of SEQ ID NO:137 and/or the VL comprises the amino acidsequence of SEQ ID NO:138; (g) the VH comprises the amino acid sequenceof SEQ ID NO:135 and/or the VL comprises the amino acid sequence of SEQID NO:136; or (h) the VH comprises the amino acid sequence of SEQ IDNO:141 and/or the VL comprises the amino acid sequence of SEQ ID NO:142.85. A binding agent that specifically binds human ILT2 comprising anantigen-binding domain comprising a heavy chain variable region (VH)comprising a VH-complementarity determining region (CDR)1, a VH-CDR2,and a VH-CDR3 from the amino acid sequence of SEQ ID NO:125; and a lightchain variable region (VL) comprising a VL-CDR1, a VL-CDR2, and aVL-CDR3 from the amino acid sequence of SEQ ID NO:126.
 86. The bindingagent of claim 85, wherein: (1) the VH comprises the VH-CDR1 comprisingthe amino acid sequence of SEQ ID NO:31, the VH-CDR2 comprising theamino acid sequence of SEQ ID NO:23, and the VH-CDR3 comprising theamino acid sequence of SEQ ID NO:24; and the VL comprises the VL-CDR1comprising amino acid sequence of SEQ ID NO:25, the VL-CDR2 comprisingamino acid sequence of SEQ ID NO:26, and the VL-CDR3 comprising theamino acid sequence of SEQ ID NO:27; (2) the VH comprises the VH-CDR1comprising the amino acid sequence of SEQ ID NO:22, the VH-CDR2comprising the amino acid sequence of SEQ ID NO:23, and the VH-CDR3comprising the amino acid sequence of SEQ ID NO:24; and the VL comprisesthe VL-CDR1 comprising the amino acid sequence of SEQ ID NO:25, theVL-CDR2 comprising the amino acid sequence of SEQ ID NO:26, and theVL-CDR3 comprising the amino acid sequence of SEQ ID NO:27; (3) the VHcomprises the VH-CDR1 comprising the amino acid sequence of SEQ IDNO:28, the VH-CDR2 comprising the amino acid sequence of SEQ ID NO:29,and the VH-CDR3 comprising the amino acid sequence of SEQ ID NO:24; andthe VL comprises the VL-CDR1 comprising the amino acid sequence of SEQID NO:25, the VL-CDR2 comprising the amino acid sequence of SEQ IDNO:26, and the VL-CDR3 comprising the amino acid sequence of SEQ IDNO:27; (4) the VH comprises the VH-CDR1 comprising the amino acidsequence of SEQ ID NO:22, the VH-CDR2 comprising the amino acid sequenceof SEQ ID NO:30, and the VH-CDR3 comprising the amino acid sequence ofSEQ ID NO:24; and the VL comprises the VL-CDR1 comprising the amino acidsequence of SEQ ID NO:25, the VL-CDR2 comprising the amino acid sequenceof SEQ ID NO:26, and the VL-CDR3 comprising the amino acid sequence ofSEQ ID NO:27; or (5) the VH comprises the VH-CDR1 comprising the aminoacid sequence of SEQ ID NO:32, the VH-CDR2 comprising the amino acidsequence of SEQ ID NO:33, and the VH-CDR3 comprising the amino acidsequence of SEQ ID NO:34; and the VL comprises the VL-CDR1 comprisingthe amino acid sequence of SEQ ID NO:35, the VL-CDR2 comprising theamino acid sequence of SEQ ID NO:36, and the VL-CDR3 comprising theamino acid sequence of SEQ ID NO:37.
 87. The binding agent of claim 85,wherein: (a) the VH has at least 80% sequence identity to the amino acidsequence of SEQ ID NO:125 and/or the VL has at least 80% sequenceidentity to the amino acid sequence of SEQ ID NO:126; or (b) the VHcomprises the amino acid sequence of SEQ ID NO:125 and/or the VLcomprises the amino acid sequence of SEQ ID NO:126.
 88. A binding agentthat specifically binds human ILT4 comprising an antigen-binding domaincomprising: (a) a heavy chain variable region (VH) comprising aVH-complementarity determining region (CDR)1, a VH-CDR2, and a VH-CDR3from the amino acid sequence of SEQ ID NO:129; and a light chainvariable region (VL) comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 fromthe amino acid sequence of SEQ ID NO:130; or (b) a VH comprising aVH-CDR1, a VH-CDR2, and a VH-CDR3 from the amino acid sequence of SEQ IDNO:127; and a VL comprising a VL-CDR1, a VL-CDR2, and a VL-CDR3 from theamino acid sequence of SEQ ID NO:128.
 89. The binding agent of claim 88,wherein for (a): (1) the VH comprises the VH-CDR1 comprising the aminoacid sequence of SEQ ID NO:63, the VH-CDR2 comprising the amino acidsequence of SEQ ID NO:55, and the VH-CDR3 comprising the amino acidsequence of SEQ ID NO:56; and the VL comprises the VL-CDR1 comprisingthe amino acid sequence of SEQ ID NO:57, the VL-CDR2 comprising theamino acid sequence of SEQ ID NO:58, and the VL-CDR3 comprising theamino acid sequence of SEQ ID NO:59; (2) the VH comprises VH-CDR1comprising the amino acid sequence of SEQ ID NO:54, the VH-CDR2comprising the amino acid sequence of SEQ ID NO:55, and the VH-CDR3comprising the amino acid sequence of SEQ ID NO:56; and the VL comprisesthe VL-CDR1 comprising the amino acid sequence of SEQ ID NO:57, theVL-CDR2 comprising the amino acid sequence of SEQ ID NO:58, and theVL-CDR3 comprising the amino acid sequence of SEQ ID NO:59; (3) the VHcomprises the VH-CDR1 comprising the amino acid sequence of SEQ IDNO:60, the VH-CDR2 comprising the amino acid sequence of SEQ ID NO:61,and the VH-CDR3 comprising the amino acid sequence of SEQ ID NO:56; andthe VL comprises the VL-CDR1 comprising the amino acid sequence of SEQID NO:57, the VL-CDR2 comprising the amino acid sequence of SEQ IDNO:58, and the VL-CDR3 comprising the amino acid sequence of SEQ IDNO:59; (4) the VH comprises the VH-CDR1 comprising the amino acidsequence of SEQ ID NO:54, the VH-CDR2 comprising the amino acid sequenceof SEQ ID NO:62, and the VH-CDR3 comprising the amino acid sequence ofSEQ ID NO:56; and the VL comprises the VL-CDR1 comprising the amino acidsequence of SEQ ID NO:57, the VL-CDR2 comprising the amino acid sequenceof SEQ ID NO:58, and the VL-CDR3 comprising the amino acid sequence ofSEQ ID NO:59; or (5) the VH comprises the VH-CDR1 comprising the aminoacid sequence of SEQ ID NO:64, the VH-CDR2 comprising the amino acidsequence of SEQ ID NO:65, and the VH-CDR3 comprising the amino acidsequence of SEQ ID NO:66; and the VL comprises the VL-CDR1 comprisingthe amino acid sequence of SEQ ID NO:67, the VL-CDR2 comprising theamino acid sequence of SEQ ID NO:68, and the VL-CDR3 comprising theamino acid sequence of SEQ ID NO:69; or wherein for (b): (1) the VHcomprises the VH-CDR1 comprising the amino acid sequence of SEQ IDNO:47, the VH-CDR2 comprising the amino acid sequence of SEQ ID NO:39,and the VH-CDR3 comprising the amino acid sequence of SEQ ID NO:40; andthe VL comprises the VL-CDR1 comprising the amino acid sequence of SEQID NO:41, the VL-CDR2 comprising the amino acid sequence of SEQ IDNO:42, and the VL-CDR3 comprising the amino acid sequence of SEQ IDNO:43; (2) the VH comprises the VH-CDR1 comprising the amino acidsequence of SEQ ID NO:38, the VH-CDR2 comprising the amino acid sequenceof SEQ ID NO:39, and the VH-CDR3 comprising the amino acid sequence ofSEQ ID NO:40; and the VL comprises the VL-CDR1 comprising the amino acidsequence of SEQ ID NO:41, the VL-CDR2 comprising the amino acid sequenceof SEQ ID NO:42, and the VL-CDR3 comprising the amino acid sequence ofSEQ ID NO:43; (3) the VH comprises the VH-CDR1 comprising the amino acidsequence of SEQ ID NO:44, the VH-CDR2 comprising the amino acid sequenceof SEQ ID NO:45, and the VH-CDR3 comprising the amino acid sequence ofSEQ ID NO:40; and the VL comprises the VL-CDR1 comprising the amino acidsequence of SEQ ID NO:41, the VL-CDR2 comprising the amino acid sequenceof SEQ ID NO:42, and the VL-CDR3 comprising the amino acid sequence ofSEQ ID NO:43; (4) the VH comprises the VH-CDR1 comprising the amino acidsequence of SEQ ID NO:38, the VH-CDR2 comprising the amino acid sequenceof SEQ ID NO:46, and the VH-CDR3 comprising the amino acid sequence ofSEQ ID NO:40; and the VL comprises the VL-CDR1 comprising the amino acidsequence of SEQ ID NO:41, the VL-CDR2 comprising the amino acid sequenceof SEQ ID NO:42, and the VL-CDR3 comprising the amino acid sequence ofSEQ ID NO:43;or (5) the VH comprises the VH-CDR1 comprising the aminoacid sequence of SEQ ID NO:48, the VH-CDR2 comprising the amino acidsequence of SEQ ID NO:49, and the VH-CDR3 comprising the amino acidsequence of SEQ ID NO:50; and the VL comprises the VL-CDR1 comprisingthe amino acid sequence of SEQ ID NO:51, the VL-CDR2 comprising theamino acid sequence of SEQ ID NO:52, and the VL-CDR3 comprising an aminoacid sequence of SEQ ID NO:53.
 90. The binding agent of claim 88,wherein: (a) the VH has at least 80% sequence identity to the amino acidsequence of SEQ ID NO:129 and/or the VL has at least 80% sequenceidentity to the amino acid sequence of SEQ ID NO:130; or (b) the VH hasat least 80% sequence identity to the amino acid sequence of SEQ IDNO:127 and/or the VL has at least 80% sequence identity to the aminoacid sequence of SEQ ID NO:128; (c) the VH comprises the amino acidsequence of SEQ ID NO:129 and/or the VL comprises the amino acidsequence of SEQ ID NO:130; or (d) the VH comprises the amino acidsequence of SEQ ID NO:127 and/or the VL comprises the amino acidsequence of SEQ ID NO:128.
 91. The binding agent of claim 82, which is(1) a whole antibody; (2) an antibody fragment comprising at least oneantigen-binding site; or (3) attached to a half-life extending moiety.92. The binding agent of claim 85, which is (1) a whole antibody; (2) anantibody fragment comprising at least one antigen-binding site; or (3)attached to a half-life extending moiety.
 93. The binding agent of claim88, which is (1) a whole antibody; (2) an antibody fragment comprisingat least one antigen-binding site; or (3) attached to a half-lifeextending moiety.
 94. The binding agent of claim 82, comprising: (a) aheavy chain comprising an amino acid sequence with 80% identity to thesequence of SEQ ID NO:148 and/or a light chain comprising an amino acidsequence with 80% identity to the sequence of SEQ ID NO:149; (b) a heavychain comprising an amino acid sequence with 80% identity to thesequence of SEQ ID NO:152 and/or a light chain comprising an amino acidsequence with 80% identity to the sequence of SEQ ID NO:153; (c) a heavychain comprising an amino acid sequence with 80% identity to thesequence of SEQ ID NO:156 and/or a light chain comprising an amino acidsequence with 80% identity to the sequence of SEQ ID NO:157; (d) a heavychain comprising the amino acid sequence of SEQ ID NO:148 and/or a lightchain comprising the amino acid sequence of SEQ ID NO:149; (b) a heavychain comprising the amino acid sequence of SEQ ID NO:152 and/or a lightchain comprising the amino acid sequence of SEQ ID NO:153; or (c) aheavy chain comprising the amino acid sequence of SEQ ID NO:156 and/or alight chain comprising the amino acid sequence of SEQ ID NO:157.
 95. Apharmaceutical composition that comprises the binding agent of claim 82and a pharmaceutically acceptable carrier, wherein the binding agent is(1) a whole antibody; (2) an antibody fragment comprising at least oneantigen-binding site; or (3) attached to a half-life extending moiety.96. A pharmaceutical composition that comprises the binding agent ofclaim 85 and a pharmaceutically acceptable carrier, wherein the bindingagent is (1) a whole antibody; (2) an antibody fragment comprising atleast one antigen-binding site; or (3) attached to a half-life extendingmoiety.
 97. A pharmaceutical composition that comprises the bindingagent of claim 88 and a pharmaceutically acceptable carrier, wherein thebinding agent is (1) a whole antibody; (2) an antibody fragmentcomprising at least one antigen-binding site; or (3) attached to ahalf-life extending moiety.
 98. An isolated polynucleotide orpolynucleotides encoding the binding agent of claim 82, wherein thebinding agent is (1) a whole antibody; or (2) an antibody fragmentcomprising at least one antigen-binding site.
 99. An isolatedpolynucleotide or polynucleotides encoding the binding agent of claim85, wherein the binding agent is (1) a whole antibody; or (2) anantibody fragment comprising at least one antigen-binding site.
 100. Anisolated polynucleotide or polynucleotides encoding the binding agent ofclaim 88, wherein the binding agent is (1) a whole antibody; or (2) anantibody fragment comprising at least one antigen-binding site.
 101. Avector or vectors comprising the polynucleotide or polynucleotides ofclaim
 98. 102. A vector or vectors comprising the polynucleotide orpolynucleotides of claim
 99. 103. A vector or vectors comprising thepolynucleotide or polynucleotides of claim
 100. 104. An isolated cellcomprising the polynucleotide or polynucleotides of claim
 98. 105. Anisolated cell comprising the polynucleotide or polynucleotides of claim99.
 106. An isolated cell comprising the polynucleotide orpolynucleotides of claim
 100. 107. An isolated cell comprising thevector or vectors of claim
 101. 108. An isolated cell comprising thevector or vectors of claim
 102. 109. An isolated cell comprising thevector or vectors of claim
 103. 110. A method of making a binding agentthat specifically binds to ILT2 and ILT4, the method comprising: (a)culturing the cell of claim 104 under conditions that result in theexpression of the binding agent, and (b) isolating the binding agent.111. A method of making a binding agent that specifically binds to ILT2,the method comprising: (a) culturing the cell of claim 105 underconditions that result in the expression of the binding agent, and (b)isolating the binding agent.
 112. A method of making a binding agentthat specifically binds to ILT4, the method comprising: (a) culturingthe cell of claim 106 under conditions that result in the expression ofthe binding agent, and (b) isolating the binding agent.
 113. A method ofmaking a binding agent that specifically binds to ILT2 and ILT4, themethod comprising: (a) culturing the cell of claim 107 under conditionsthat result in the expression of the binding agent, and (b) isolatingthe binding agent.
 114. A method of making a binding agent thatspecifically binds to ILT2, the method comprising: (a) culturing thecell of claim 108 under conditions that result in the expression of thebinding agent, and (b) isolating the binding agent.
 115. A method ofmaking a binding agent that specifically binds to ILT4, the methodcomprising: (a) culturing the cell of claim 109 under conditions thatresult in the expression of the binding agent, and (b) isolating thebinding agent.
 116. A method of disrupting, inhibiting, or blocking in amixture of cells and/or in a subject at least one of the following: (a)the binding of ILT2 and/or ILT4 to a MHC I molecule, and (b) MHCI-induced ILT2 and/or ILT4 activity; the method comprising contactingthe cells with, or administering to the subject, the binding agent ofclaim
 82. 117. A method of disrupting, inhibiting, or blocking in amixture of cells and/or in a subject at least one of the following: (a)the binding of ILT2 to a MHC I molecule in a mixture of cells, and (b)MHC I-induced ILT2 activity; the method comprising contacting the cellswith, or administering to the subject, the binding agent of claim 85.118. A method of disrupting, inhibiting, or blocking in a mixture ofcells and/or in a subject at least one of the following: (a) the bindingof ILT4 to a MHC I molecule in a mixture of cells, and (b) MHC I-inducedILT4 activity; the method comprising contacting the cells with, oradministering to the subject, the binding agent of claim
 88. 119. Amethod of disrupting, inhibiting, or blocking in a mixture of cellsand/or in a subject at least one of the following: (a) the binding ofILT2 and/or ILT4 to a MHC I molecule, and (b) MHC I-induced ILT2 and/orILT4 activity; the method comprising contacting the cells with, oradministering to the subject, the pharmaceutical composition of claim95.
 120. A method of disrupting, inhibiting, or blocking in a mixture ofcells and/or in a subject at least one of the following: (a) the bindingof ILT2 to a MHC I molecule in a mixture of cells, and (b) MHC I-inducedILT2 activity; the method comprising contacting the cells with, oradministering to the subject, the binding agent of claim
 96. 121. Amethod of disrupting, inhibiting, or blocking in a mixture of cellsand/or in a subject at least one of the following: (a) the binding ofILT4 to a MHC I molecule in a mixture of cells, and (b) MHC I-inducedILT4 activity; the method comprising contacting the cells with, oradministering to the subject, the binding agent of claim
 97. 122. Amethod of (a) disrupting, inhibiting, or blocking ILT2- and ILT4-inducedsuppression of myeloid cells; (b) inhibiting or decreasingmyeloid-derived suppressor cell (MDSC) activity; (c) enhancing orincreasing natural killer (NK) cell activity, or (d) enhancing orincreasing cytolytic T lymphocyte (CTL) activity; the method comprisingcontacting respectively the myeloid cells of (a); the MDSCs of (b); theNK cells of (c); or the CTLs of (d) with the binding agent of claim 82.123. A method of (a) disrupting, inhibiting, or blocking ILT2-inducedsuppression of myeloid cells; (b) inhibiting or decreasingmyeloid-derived suppressor cell (MDSC) activity; (c) enhancing orincreasing natural killer (NK) cell activity, or (d) enhancing orincreasing cytolytic T lymphocyte (CTL) activity; the method comprisingcontacting respectively the myeloid cells of (a); the MDSCs of (b); theNK cells of (c); or the CTLs of (d) with the binding agent of claim 85.124. A method of (a) disrupting, inhibiting, or blocking ILT4-inducedsuppression of myeloid cells; (b) inhibiting or decreasingmyeloid-derived suppressor cell (MDSC) activity; (c) enhancing orincreasing natural killer (NK) cell activity, or (d) enhancing orincreasing cytolytic T lymphocyte (CTL) activity; the method comprisingcontacting respectively the myeloid cells of (a); the MDSCs of (b); theNK cells of (c); or the CTLs of (d) with the binding agent of claim 88.125. A method of (a) disrupting, inhibiting, or blocking the binding ofILT2 and/or ILT4 to a MHC I molecule in a subject; (b) disrupting,inhibiting, or blocking MHC I-induced ILT2 and/or ILT4 activity in asubject; (c) disrupting, inhibiting, or blocking ILT2 or ILT4-inducedsuppression of myeloid cells in a subject; (d) inhibiting or decreasingMDSC activity in a subject; (e) enhancing or increasing NK cell activityin a subject; (f) enhancing or increasing CTL activity in a subject; (g)treating cancer in a subject; (h) inhibiting tumor growth in a subject;(i) increasing or enhancing an immune response to a tumor or tumor cellsin a subject; (j) inhibiting tumor relapse or tumor regrowth in asubject; or (k) activating myeloid cells in the tumor microenvironmentin a subject with a tumor; the method comprising administering to thesubject a therapeutically effective amount of the binding agent of claim82.
 126. A method of (a) disrupting, inhibiting, or blocking the bindingof ILT2 and/or ILT4 to a MHC I molecule in a subject; (b) disrupting,inhibiting, or blocking MHC I-induced ILT2 and/or ILT4 activity in asubject; (c) disrupting, inhibiting, or blocking ILT2 or ILT4-inducedsuppression of myeloid cells in a subject; (d) inhibiting or decreasingMDSC activity in a subject; (e) enhancing or increasing NK cell activityin a subject; (f) enhancing or increasing CTL activity in a subject; (g)treating cancer in a subject; (h) inhibiting tumor growth in a subject;(i) increasing or enhancing an immune response to a tumor or tumor cellsin a subject; (j) inhibiting tumor relapse or tumor regrowth in asubject; or (k) activating myeloid cells in the tumor microenvironmentin a subject with a tumor; the method comprising administering to thesubject a therapeutically effective amount of the binding agent of claim85.
 127. A method of (a) disrupting, inhibiting, or blocking the bindingof ILT2 to a MHC I molecule in a subject; (b) disrupting, inhibiting, orblocking MHC I-induced ILT4 activity in a subject; (c) disrupting,inhibiting, or blocking ILT2 or ILT4-induced suppression of myeloidcells in a subject; (d) inhibiting or decreasing MDSC activity in asubject; (e) enhancing or increasing NK cell activity in a subject; (f)enhancing or increasing CTL activity in a subject; (g) treating cancerin a subject; (h) inhibiting tumor growth in a subject; (i) increasingor enhancing an immune response to a tumor or tumor cells in a subject;(j) inhibiting tumor relapse or tumor regrowth in a subject; or (k)activating myeloid cells in the tumor microenvironment in a subject witha tumor; the method comprising administering to the subject atherapeutically effective amount of the binding agent of claim
 88. 128.A method of (a) disrupting, inhibiting, or blocking the binding of ILT2and/or ILT4 to a MHC I molecule in a subject; (b) disrupting,inhibiting, or blocking MHC I-induced ILT2 and/or ILT4 activity in asubject; (c) disrupting, inhibiting, or blocking ILT2 or ILT4-inducedsuppression of myeloid cells in a subject; (d) inhibiting or decreasingMDSC activity in a subject; (e) enhancing or increasing NK cell activityin a subject; (f) enhancing or increasing CTL activity in a subject; (g)treating cancer in a subject; (h) inhibiting tumor growth in a subject;(i) increasing or enhancing an immune response to a tumor or tumor cellsin a subject; (j) inhibiting tumor relapse or tumor regrowth in asubject; or (k) activating myeloid cells in the tumor microenvironmentin a subject with a tumor; the method comprising administering to thesubject a therapeutically effective amount of the pharmaceuticalcomposition of claim
 95. 129. A method of (a) disrupting, inhibiting, orblocking the binding of ILT2 and/or ILT4 to a MHC I molecule in asubject; (b) disrupting, inhibiting, or blocking MHC I-induced ILT2and/or ILT4 activity in a subject; (c) disrupting, inhibiting, orblocking ILT2 or ILT4-induced suppression of myeloid cells in a subject;(d) inhibiting or decreasing MDSC activity in a subject; (e) enhancingor increasing NK cell activity in a subject; (f) enhancing or increasingCTL activity in a subject; (g) treating cancer in a subject; (h)inhibiting tumor growth in a subject; (i) increasing or enhancing animmune response to a tumor or tumor cells in a subject; (j) inhibitingtumor relapse or tumor regrowth in a subject; or (k) activating myeloidcells in the tumor microenvironment in a subject with a tumor; themethod comprising administering to the subject a therapeuticallyeffective amount of the pharmaceutical composition of claim
 96. 130. Amethod of (a) disrupting, inhibiting, or blocking the binding of ILT2 toa MHC I molecule in a subject; (b) disrupting, inhibiting, or blockingMHC I-induced ILT4 activity in a subject; (c) disrupting, inhibiting, orblocking ILT2 or ILT4-induced suppression of myeloid cells in a subject;(d) inhibiting or decreasing MDSC activity in a subject; (e) enhancingor increasing NK cell activity in a subject; (f) enhancing or increasingCTL activity in a subject; (g) treating cancer in a subject; (h)inhibiting tumor growth in a subject; (i) increasing or enhancing animmune response to a tumor or tumor cells in a subject; (j) inhibitingtumor relapse or tumor regrowth in a subject; or (k) activating myeloidcells in the tumor microenvironment in a subject with a tumor; themethod comprising administering to the subject a therapeuticallyeffective amount of the pharmaceutical composition of claim
 97. 131. Apharmaceutical composition, comprising: (a) a means for inhibiting theinteraction between ILT2 and/or ILT4 and MHC Class I; and (b) apharmaceutically acceptable carrier.
 132. A combination comprising ameans for inhibiting the interaction between ILT2 and/or ILT4 and MHCClass I (e.g., on tumor cells), and an immune checkpoint inhibitor.